In vitro behavior of bioactive phosphate glass–ceramics from the system P2O5–Na2O–CaO containing titania

Soda lime phosphate bioglass–ceramics with incorporation of small additions of TiO₂ were prepared in the metaphosphate and pyrophosphate region, using an appropriate two-step heat treatment of controlled crystallization defined by differential thermal analysis results. Identification and quantification of crystalline phases precipitated from the soda lime phosphate glasses were performed using X-ray diffraction analysis. Calcium pyrophosphate (β-Ca₂P₂O₇), sodium metaphosphate (NaPO₃), calcium metaphosphate (β-Ca(PO₃)₂), sodium pyrophosphate (Na₄P₂O₇), sodium calcium phosphate (Na₄Ca(PO₃)₆) and sodium titanium phosphate (Na₅Ti(PO₄)₃) phases were detected in the prepared glass–ceramics. The degradation of the prepared glass–ceramics was carried out for different periods of time in simulated body fluid at 37 °C using granules in the range 0.300–0.600 mm. The released ions were estimated by atomic absorption spectroscopy and the surface textures were measured by scanning electron microscopy. Investigation of in vitro bioactivity of the prepared glass–ceramics was done by the measurement of the infrared reflection spectra for the samples after immersion in the simulated body fluid for different periods at 37 °C. The result showed that no apatite layer was formed on the surface of the samples and the dominant phase remained on the surface was β-Ca₂P₂O₇, which is known for its bioactivity.     

The role of strontium and potassium on crystallization and bioactivity of Na2O-CaO-P2O5-SiO2 glasses

The effect of SrO/CaO and K₂O/Na₂O replacements on the crystallization process of glasses based on Na₂O-CaO-P₂O₅-SiO₂ system was investigated. The glasses were thermally treated through controlled heat treatment regimes to obtain glass ceramic materials. Combeite Na₂Ca₂Si₃O₉, sodium calcium silicate Na₂Ca₃Si₆O₁₆, wollastonite solid solution, and whitlockite Ca₃(PO₄)₂ were identified as major crystalline phases in the prepared thermally treated glasses. No potassium and strontium-containing phases could be detected in the glass-ceramics; potassium seems to be accommodated in the wollastonite structure, while strontium might be incorporated in the sodium calcium silicate structure.The surface reactivity of the prepared glass-ceramic specimens was also studied in vitro in Kokobo's simulated body fluid (SBF). EDAX, SEM, inductively coupled plasma ICP, and FTIR were used to examine the formation of apatite layer's surface and characterize the glass ceramic surface and SBF compositional changes. A decrease in the bioactivity of the glass ceramic was observed as Na₂O was replaced by K₂O. Strontium together with calcium ions in the apatite layer formed was detected with SrO/CaO replacement.The role played by the glass oxide constituents in determining the crystallization and bioactivity behaviour of the prepared thermally treated glasses was discussed.     

Structural and thermal characterization of CaO–MgO–SiO2–P2O5–CaF2 glasses

The influence of varying the CaO/MgO ratio on the structure and thermal properties of CaO–MgO–SiO₂–P₂O₅–CaF₂ glasses was studied in a series of eight glass compositions in the glass forming region of diopside (CaMgSi₂O₆)–fluorapatite [Ca₅(PO₄)₃F]–wollastonite (CaSiO₃) ternary system. The melt-quenched glasses were characterized for their structure by infrared spectroscopy (FTIR) and magic angle spinning (MAS)-nuclear magnetic resonance (NMR) spectroscopy. Silicon is predominantly present as Q² (Si) species, while phosphorus tends to coordinate in orthophosphate environment. The sintering and crystallization parameters of the glasses were obtained from differential thermal analysis (DTA) while crystalline phase fractions in the sintered glass–ceramics were analyzed by X-ray diffraction adjoined with Rietveld refinement. Diopside, fluorapatite, wollastonite and pseudowollastonite crystallized as the main crystalline phases in all the glass–ceramics with their content varying with respect to variation in CaO/MgO ratio in glasses. The implications of structure and sintering behaviour of glasses on their bioactivity were discussed.     

Crystallization and properties of glasses based on diopside–Ca-Tschermak’s–fluorapatite system

The crystallization characteristics of glasses based on compositions in the diopside [CaMgSi₂O₆]–Ca-Tschermak’s [CaAl₂SiO₆]–fluorapatite [Ca₅(PO₄)₃F] system have been investigated. The effect of Ca-Tschermak’s/diopside replacement, at constant Ca₅(PO₄)₃F content, on the crystallization characteristics of the glasses and the solid solution phases formed, as well as the resulting microstructure, are traced by differential thermal analysis (DTA), X-ray diffraction analysis (XRD) and scanning electron microscopy (SEM).Various pyroxene solid solutions together with fluorapatite phases are detected by XRD analysis. There is a preferential tendency for diopside to capture Ca-Tschermak’s in its structure forming pyroxene solid solution of diopsidic type. The maximum concentration of CaAl₂SiO₆ that could be accommodated in the diopside structure was 25%. Above this percentage, gehlenite Ca₂Al₂SiO₇ also developed. However, there was no solid solution formed between pyroxene and fluorapatite.The thermal expansion coefficients (α-values) and microhardness of the glasses and glass–ceramics were determined. The data of the glasses were correlated to the internal structure of the glasses, nature and role played by glass forming cations. However, the properties of the crystalline glasses were mainly attributed to different factors including the crystalline phases formed, residual glassy phase and the microstructures.     

Calcium Cl/OH-apatite,Cl/OH-apatite/Al2O3 and Ca3(PO4)2 fibre nonwovens: Potential ceramic components for osteosynthesis

Polycrystalline calcium phosphate ((Cl/OH)Ap = Ca₅(PO₄)₃(OH/Cl); TCP = Ca₃(PO₄)₂) fibres were prepared from aqueous solutions of calcium chloride and phosphoric acid using poly(ethylene oxide) (PEO) as spinning aid. Generation of nonwoven materials was accomplished via rotary jet spinning. Polycrystalline (Cl/OH)Ap fibres 10–25 μm in diameter were obtained with 37% ceramic yield by pyrolysis of the green fibres followed by sintering at 1150 °C in air. X-ray diffraction (XRD) analysis provided evidence for apatite formation starting at 650 °C while (Cl/OH)Ap ceramic fibres were obtained at 1100 °C via transformation through intermediate dicalcium dichloride hydrogen phosphate (Ca₂Cl₂(HPO₄)) and calcium pyrophosphate (Ca₂P₂O₇) phases. A glass-forming Al-based additive was applied to enhance the mechanical properties of the Cl/OH)Ap ceramic fibres and indeed resulted in the formation of (Cl/OH)Ap/Al₂O₃ fibres with improved mechanical stability. Finally, TCP, (Cl/OH)Ap and (Cl/OH)Ap/Al₂O₃ fibres were subjected to seeding with mesenchymal stem cells. Negligible cytotoxicity is observed.     

Influence of ZrO2 oxide on the properties and crystallization of calcium fluoro-alumino-silicate glasses

The impact of ZrO₂ content of the glass on the formation, properties and crystallization of glass ionomer cements (GICs) was investigated. Glass series based on SiO₂–Al₂O₃–ZrO₂–P₂O₅–CaO–CaF₂ system was synthesized and studied. The cements were characterized using a setting time, flexural strength, fracture toughness and in vitro biocompatibility test. The setting time of the ionomer cement increased with increasing the ZrO₂ content of the glass. The cements showed a slight decrease of cell biocompatibility with increase the ZrO₂ oxide content in the glasses. The results also showed that the flexural strength and the fracture toughness of the cements increased with immersion time and ZrO₂ oxide content. The crystallization characteristics of the glasses were investigated by differential scanning calorimeter (DSC) and X-ray diffraction analysis (XRD). The addition of ZrO₂ oxide in the glasses led to increase both the glass transition and crystallization temperatures. Fluorapatite [Ca₅(PO₄)₃F], mullite [Al₆Si₂O₁₃], cristobalite [SiO₂] and zircon [ZrSiO₄] phases were crystallized from the investigated glasses. The role played by the glass oxide constituents in determining the setting time, mechanical properties and crystallization characteristics of the prepared glass ionomer was discussed.     

Bioactive fluorapatite-containing glass ceramics

Fluorapatite-containing glass ceramics were synthesized on the basis of the glass-forming system SiO₂–Al₂O₃–P₂O₅–CaO–CaF₂. The introduction of phosphorus and fluorine containing materials, as well as the specific regime of heat treatment of the glasses gave glass ceramic materials with crystalline phases of the apatite group—fluorapatite (Ca₁₀(PO₄)₆F₂), apatite (Ca₃(PO₄)₂), vitlokite (Ca₉P₆O₂₄), etc. The X-ray phase analysis showed that the main phase in all the glass ceramic samples was fluorapatite. The phase composition, structure and some of the basic properties of the glass ceramic samples were determined.     

Gel-derived SiO2–CaO–P2O5 bioactive glasses and glass-ceramics modified by SrO addition

The effect of SrO substitution for CaO in two sol–gel glasses with different chemical compositions (mol%) A2Sr: (54−x)CaO–xSrO–6P₂O₅–40SiO₂ and S2Sr: (16−x)CaO–xSrO–4P₂O₅–80SiO₂ (x=0, 1, 3 and 5) stabilized at 700 °C on their structure (XRD, FTIR) and bioactive properties (SBF test) was investigated. Preliminary in vitro tests using human articular chondrocytes of selected A2Sr glass were also conducted. Moreover, the subject of this study was to detect the changes on material properties after heat treatment at 1300 °C. The results show that the effect of strontium substitution on structure, bioactivity and crystallization after treatment at both the above temperatures strongly depends on CaO/SiO₂ molar ratio. The presence of 3–5 mol% of strontium ions creates more expanded glass structure but does not markedly affect crystallization ability after low temperature treatment. Sintering at 1300 °C of A2 type glasses results in crystallization of pseudowollastonite, hydroxyapatite and also Sr-substituted hydroxyapatite for 3–5 mol% of SrO substitution. The increase of strontium concentration in silica-rich materials after sintering leads to appearance of calcium strontium phosphate instead of calcium phosphate. Bioactivity evaluation indicates that substitution of Sr for Ca delays calcium phosphate formation on the materials surface only in the case of silica-rich glasses treated at 700 °C. Calcium-rich glasses, after both temperature treatments, reveals high bioactivity, while crystal size of hydroxyapatite decreases with increasing Sr content. High temperature treatment of high-silica glasses inhibits their bioactivity. Preliminary in vitro tests shows Sr addition to have a positive effects on human articular chondrocytes proliferation and to inhibit cell matrix biomineralization.     

Raman imaging as a useful tool to describe crystallization of aluminum/iron-containing polyphosphate glasses

Polyphosphate glasses are materials of a wide spectrum of applications in many fields. The subject of the work is polyphosphate glasses containing aluminum and iron. Three compositions of the glasses were obtained and the materials have been characterized in terms of their crystallization. The differences in crystallization behavior between powder and bulk materials were compared. The crystallized materials were analyzed by Raman scattering spectroscopy and X-ray diffraction method. It was evidenced that depending on the glass composition the main crystalline phases were Al(PO₃)₃, AlPO₄, FePO₄, Fe₃(P₂O₇), Fe₄(P₂O₇)₃, FePO₄. The glass crystallization leads to enrichment of the residual glassy phase in P₂O₅ and increases its polymerization. Thus, it was observed the glass inhomogeneities are being increased due to crystallization. The two dimensions spectral maps of the bulk crystallized samples were executed to describe the mechanism and type of crystallization. The depth profiling proves the differences between surface and interior phase composition.     

Bioactive glass-ceramics prepared by powder sintering and crystallization of polyphosphate glass containing strontium

Melt-quenching method was employed for obtaining a glass-ceramic with the following composition 42P₂O₅·40CaO·5SrO·10Na₂O·3TiO₂ (mol%) glass. The crystallization and sintering behavior of glass have been studied by using DTA, HSM, XRD, FTIR and SEM methods. It was determined that the surface and volume crystallization mechanisms act simultaneously in bulk glass samples. The comparison of DTA and HSM data revealed that the sintering and crystallization processes are independent. The sintered calcium phosphate glass-ceramic which contained bioactive β-Ca₃(PO₄)₂ and β-Ca₂P₂O₇ phases was successfully prepared. It was determined that during crystallization the primary phase in the precipitate was β-Ca(PO₃)_2. Other phases appearing in the resulting glass-ceramic were: α-Ca₂P₂O₇, γ-Ca₂P₂O₇, Ca₄P₆O₁₉ and CaHPO₄(H₂O)₂. Crystalline phases containing Sr and Ti were not detected. SEM analysis of the glass-ceramic microstructure revealed surface crystallization of glass particles and plate-like morphology of crystal growth. The result of the in vitro bioactivity showed that no apatite layer was formed on the surface of the as-prepared glass-ceramic samples after immersion in the simulated body fluid (SBF).     

Structural investigations on P2O5-CaO-Na2O-K2O: SrO bioactive glass ceramics

In the present work, glasses of a particular composition (60-x) P₂O₅-20CaO-17Na₂O-3K₂O: xSrO (0.5≤x≤1.5) mol% were synthesized using conventional melt quenching technique. Further, samples were characterized by X-ray diffraction (XRD), Scanning Electron Microscopy (SEM), Differential Thermal Analyses (DTA) techniques and Fourier Transform Infrared (FT-IR) spectra. In vitro bioactivity was evaluated by soaking glass ceramic powders in SBF solution for 7 and 15 days. XRD patterns of glass ceramics have clearly confirmed the formation of various crystalline phases K₂Sr(PO₃)₄, α-Ca₂P₂O₇, Ca₂Sr(PO₄)₂, Ca₅(PO₄)₃(OH) and Ca₃(PO₄)₂. Random spreading of uneven sized micro crystals with distinct boundaries in the glass matrix have been observed from SEM pictures. DTA scans revealed an increase in the content of SrO with heating rate causes the glass transition (T_g) and crystallization temperatures (T_c) towards lower side, that confirms the decrease in rigidity of glass network. FT-IR spectra showed that there is an increase in the degree of structural disorder and the formation of a crystalline hydroxyapatite layer with soaking time. From the analyses of all the above results, it can be concluded that the sample doped with 1.5 mol% of strontium is found to exhibit high bioactivity.     

Enhancement of glass-ceramic performance by TiO2 doping: In vitro cell viability,proliferation, and differentiation

A new TiO₂-containing bioactive glass and glass-ceramics based on 50SiO₂-(45-X)CaO-(XTiO₂)-5P₂O₅ system was designed using a sol–gel technique (where X = 5, 7.5 and 10 wt %). The roles of the crystallization behavior and physicochemical characteristics of the designed glass and glass-ceramics which were played in the introduction of TiO₂ substitutions were investigated. Moreover, cell proliferation and differentiation were evaluated against human osteosarcoma cells (Saos-2). The TiO₂/CaO replacements led to the formation of a stronger glass structure and thus increased thermal parameters and the chemical stabilization of the designed materials. The FTIR data confirmed the existence of Ti within the glass and glass-ceramics samples, and no remarkable effect on their chemical integrity was observed. The XRD patterns indicated that calcium-containing minerals, including Ca₂SiO₄,Ca₃(PO₄)₂, Ca(Ti,Si)O₅, CaTiSiO₅, and Ca₁₅(PO₄)₂·(SiO₄)₆ phases were developed as a role of structure/texture under the applied heat-treatment. The results of the cytotoxicity test proved that a safe sample dose is 12–50 μg/ml, at which cell viability is ≥ 85%. The cell differentiation determined by ALP test proved the superiority of glass-ceramics compared with their native glasses. Therefore, the obtained materials could be safely used as novel biocompatible materials for the regeneration of bone tissue.     

The dissolution behavior in alkaline solutions of a borosilicate glass with and without P2O5

There are a variety of applications for glasses in alkaline environments, including glass fibers and glass‐coated steel to reinforce concrete structures. To understand how a simple glass reacts in such environments, the dissolution behavior of a 25Na₂O–25B₂O₃–50SiO₂ (mol%) glass, doped with and without 3 mol% P₂O₅, in pH 12 KOH and pH 12 KOH saturated with Ca²⁺ ions was studied. Ca²⁺ ions in the solution significantly reduce the glass dissolution rate by forming a passivating calcium silicate hydrate (C–S–H) gel layer on the glass surface. When these corroded glasses were then exposed to Ca‐free KOH, the C–S–H layer redissolves into the undersaturated solution and the glass dissolution rate increases. For phosphate‐doped borosilicate glass, PO₄^3? units released from the dissolving glass react with Ca²⁺ ions in saturated solutions to form crystalline hydroxylapatite on the glass surface, but this layer does not protect the glass from corrosion as well as the C–S–H does. The nature of the C–S–H layer was characterized by Raman spectroscopy, which reveals a gel layer constituted mainly of silicate anions.     

Transparent CaF2 surface crystallized CaO–2B2O3 glass possessing efficient photocatalytic and antibacterial properties

This study aims to fabricate surface crystallized transparent calcium borate glass (CaO–2B₂O₃) for photocatalytic and antibacterial applications. The CaO–2B₂O₃ glass was fabricated by using the conventional melt-quenching technique. Instead of using traditional high temperature and longer soaking time heat-treatment, the acid etching method was adopted to get surface crystallization. Surface etching of as-quenched glass was performed at room temperature by using three different concentrations of hydrogen fluoride in order to attain the different amount of calcium fluoride crystals at the surface. The characterization of surface crystallized glass was performed with an X-ray diffraction pattern and scanning electron microscope-EDS mapping system. Sufficient transparency (65%) was retained even at highest crystallization of glass surface. Surface crystallization with CaF₂ induces hydrophilicity and photocatalytic character in glasses which was evaluated with contact angle measurements and smart resazurin (Rz) ink test. Around 68% of methylene blue (MB) dye degradation was also displayed by the crystallized glass. Crystallized glasses portrayed good antibacterial property against Escherichia coli (gram-negative bacteria). Ninety-nine per cent of bacterial depletion was recorded in 3 hours exposure time with surface crystallized glass without any external intervention. Interesting morphological changes were observed in bacterial shape and physical appearance under field emission scanning electron microscope after exposure to crystallized glasses.     

Magnetic Properties of Iron Phosphate Glass and Glass‐Ceramics

Magnetic properties of crystallized iron phosphate glasses and relationship between structural and magnetic properties modifications that occur during crystallization have been investigated. Iron phosphate glass exhibits the spin‐glass (SG) behavior and represents a prototype of solid with disordered spatially distributed magnetic moments. Glass of the composition 43Fe₂O₃–57P₂O₅ (wt%) was heat‐treated in air at 893, 923, and 1073 K for 24 h. The samples were studied using X‐ray diffraction, Raman spectroscopy, and dc magnetic measurements. The magnetic measurements show dominant antiferromagnetic (AF) interactions for all samples. The starting glass exhibits SG behavior, whereas magnetic behavior of samples heat‐treated at 893 and 923 K, which contain Fe₃(P₂O₇)₂ crystalline phase embedded in glass matrix, is ascribed to a mixture of superparamagnetism and SG behavior. In the sample heat‐treated at 1073 K, several peaks in the magnetization curves were observed which correspond to the various crystalline phases present in the sample: Fe₃(P₂O₇)₂, Fe₄(P₂O₇)₃ and Fe(PO₃)₃. Hysteresis loops show paramagnetic behavior at 300 K. Small curvature is present at low temperature (5 K) that can be ascribed to the AF ordering in the samples.     

Calcium phosphate bioceramics synthesized from eggshell powders through a solid state reaction

Everyday millions of tons of eggshells are produced as biowaste around the world. Most of this waste is disposed of in landfills without any pretreatment. Eggshells in landfills produce odors and promote microbial growth as they biodegrade. The present invention provides an environmentally beneficial and cost-effective method of producing calcium phosphate bioceramics (hydroxyapatite or tricalcium phosphate) from eggshell waste. In this investigation, heat treatment produced solid state reactions between eggshell powders and dicalcium phosphate dihydrate (CaHPO₄·2H₂O, DCPD) or calcium pyrophosphate (Ca₂P₂O₇). When eggshell powders (CaO) and DCPD were heat treated at 1150 °C for 3 h, only a single hydroxyapatite (HA) phase was found; no diffraction peaks of starting materials and no β-TCP were observed. The XRD patterns of the product fabricated from raw eggshell powders (CaCO₃) and Ca₂P₂O₇ heat treated at 1100 °C for 3 h showed that almost only pure β-TCP remained with a trace amount of HA. The calcium phosphate ceramic synthesized from eggshell powders contains several important trace elements such as Na, Mg and Sr.     

Elucidating the Effect of Iron Speciation (Fe2+/Fe3+) on Crystallization Kinetics of Sodium Aluminosilicate Glasses

We report on the influence of Fe₂O₃ on the crystallization kinetics of nepheline (Na₂O·Al₂O₃·2SiO₂)‐based sodium aluminosilicate glasses. A series of glasses with varying Al₂O₃/Fe₂O₃ content were synthesized in the system 25Na₂O–(25–x) Al₂O₃–xFe₂O₃–50SiO₂ (x varies between 0 and 5 mol%) through melt‐quench technique. A systematic set of experiments were performed to elucidate the influence of iron speciation (Fe²⁺/Fe³⁺) on the crystallization kinetics of these glasses including: (1) obtaining the details of nonisothermal crystallization kinetics by differential scanning calorimetry, (2) determining the influence of heat treatment on the structure and iron coordination in glasses by X‐ray photoelectron spectroscopy and wet chemistry, and (3) following the crystalline phase evolution in glasses in air and inert environments by X‐ray diffraction and scanning electron microscopy. The crystallization of two polymorphs of NaAlSiO₄—carnegieite (orthorhombic) and nepheline (hexagonal)—was observed in all the glasses, wherein the incorporation of iron promotes the formation of nepheline over carnegieite while shifting the crystallization mechanism from surface to volume. The influence of environment (air versus inert) and iron content on the crystallization kinetics of these glasses is contextualized from the perspective of the devitrification problem usually observed in sodium‐ and alumina‐rich high level nuclear waste glasses.     

Crystallization Kinetics of Superionic Conductive Al(B,La)‐ Incorporated LiTi2(PO4)3 Glass‐Ceramics

For the purpose of developing high‐performance glass‐ceramic superionic conductor, the controllable precipitation of LiTi₂(PO₄)₃‐like superionic conducting phase in the Li₂O–TiO₂–P₂O₅ glass system was studied. Al with B or La co‐incorporated LiTi₂(PO₄)₃‐based glass‐ceramics were prepared by the crystallization of the corresponding original glasses. Compared with the sole Al‐incorporated LiTi₂(PO₄)₃‐based glass‐ceramics, the ionic conductivity shows an increase for the boron co‐incorporated one and a decrease for the lanthanum co‐incorporated one. Through the further in‐depth analysis based on the methods of DSC and X‐ray diffractive technique, this opposite change in ion conductivity was ascribed to the alterations of crystallization mechanism together with quantity of crystal phases within the glass‐ceramics.. The boron addition promoted the precipitation of LiTi₂(PO₄)₃ phase and restrained the precipitation of second phase. The highest ionic conductivity 1.3 × 10^?3 S/cm at 25°C was obtained through the heat treatment of B and Al co‐incorporated glassy samples at 900°C for 12 h. These inorganic solid electrolytes have a potential application in lithium batteries or other electrochemical ionic devices.     

Fabrication and in vitro studies on bioactive borate glasses containing dopant chromium sulfate

This research aims to assess the bioactive properties of the modified borate glasses containing extremely low concentrations (≤5 mol.%) from chromium sulfate (Cr₂(SO₄)₃). The glasses in the system xCr₂(SO₄)₃.(60–x)B₂O₃.15CaO.15Na₂O.10P₂O₅, where x = 0, 1, 2, and 5 mol.% were prepared by the melt quenching technique. All glass samples have been treated thermally at 600 °C for 6 h. Fourier Transform Infrared (FTIR) spectroscopy, Scanning Electron Microscopy (SEM), and X-ray Diffraction (XRD) measurements were carried out to differentiate between the structural changes before and after soaking in the simulated body fluid (SBF) at about 37 °C for 1, 2, and 3 weeks. Glass-ceramic samples have showed sharper peaks that are identified using X-ray diffraction data. These crystalline phases are indexed to crystalline calcium borate (Ca₂B₂O₃) and calcium phosphate (Ca₃(PO₄)₂). In vitro tests, FTIR spectra revealed two small bands in the 560-610 cm⁻¹ range which might be assigned to the formation of a hydroxyapatite layer (HA). The formation of HA was also confirmed by XRD results, particularly after immersion in SBF for 21 days. The study suggests that the presently studied glasses containing Cr₂(SO₄)₃ can possess good bioactivity which might be considered to be suitable for some bio and medical applications.     

Fluorophosphate glasses activated by rare-earth ions and AgBr

Analysis of the absorption band position for colloidal silver in fluorophosphate glasses of the composition (0.95 ? x ? y)(MgCaBaSrAl₂F₁₄)-0.05Ba(PO₃)₂-xPbF₂-yLnF₃ (where Ln = Eu, Ce, Sm, Tb; 0 ?? x ?? 0.2; y = 0.01, 0.02) with small additives of AgBr (0.04 wt % above 100%) has been performed. It has been shown that joint introduction of AgBr and EuF₃ with additional heat treatment of the glasses below the temperature of the onset of crystallization leads to a rise of the plasmon absorption band of silver nanoparticles. It has been assumed that the reason for the observed shift of the plasmon absorption band is the formation of a ??0.5-nm-thick shell of AgBr on the surface of a metallic Ag _n ⁰ -cluster.