Optimization of electrical conductivity in the Na2O-P2O5-AlF3-SO3 glass system

We report on the individual roles of charge carrier density and network modification in sodium ion conducting glasses from the Na₂O-P₂O₅-SO₃-AlF₃ (NAPFS) system. For this, a broad range of glass compositions was considered across the series of 44Na₂O/(56 – x − y)P₂O₅/xAlF₃/ySO₃, 47Na₂O/(53 − x − y)P₂O₅/xAlF₃/ySO₃, and 50Na₂O/(50 − x − y)P₂O₅/xAlF₃/ySO₃, with x = 8, 12, 16, 20 and y = 0, 5, 7, 10, 12. Impedance spectroscopy was conducted on these glasses at frequencies from 10⁻² to 10⁶ Hz and over temperatures from 50 to 250°C, and complemented by structural analyses using Raman spectroscopy and nuclear magnetic resonance data. While the trends in dc conductivity and activation energy follow that of Na₂O content (increasing from 44 to 50 mol%), substantial enhancement of conductivity (by about two orders of magnitude) and correspondingly lower activation energy were also found for constant Na₂O concentration when adjusting SO₃ or AlF₃ within specific limits of glass structure.     

Dielectric polarizability of SiO2 in niobiosilicate glasses

Understanding the mechanisms contributing to dielectric properties of glasses is critical for designing new compositions for microwave frequency applications. In this work, dielectric permittivity was measured using a cavity perturbation technique at 10 GHz for a series of niobiosilicate glasses with the compositions (100-2x)SiO₂- xNb₂O₅- xLi₂O where x = 32.5, 30, 25, and 15 mol%. Permittivity measurements and glass compositions were used to calculate the polarizability of each cation-anion unit in the glass network using the Clausius-Mossotti equation. The SiO₂ polarizability in niobiosilicates was calculated to be 6.16 ų, which is much higher than the SiO₂ polarizability in fused silica glass (5.25 ų), alkali modified silicates (5.37 ų), and aluminosilicates (5.89 ų). The increasing trend in SiO₂ polarizability is attributed to the disruption in the connectivity of the SiO₄ tetrahedral network as it accommodates different network formers. The high SiO₂ polarizability of 6.16 ų accurately predicts measured dielectric permittivity when Nb₂O₅ = 25, 30, and 32.5 mol%, but overpredicts measured permittivity when Nb₂O₅ ≤ 15 mol%, which is attributed to a decrease in SiO₂ polarizability as the percentage of corner sharing SiO₄ tetrahedra with NbO₆ octahedra goes down. This work demonstrates that SiO₂ polarizability depends on chemistry and connectivity of the glass, which has important implications in designing glass compositions for microwave frequency applications.     

Effect of Niobium Oxide on the Structure and Properties of Melt‐Derived Bioactive Glasses

The effects of adding Nb₂O₅ on the physical properties and glass structure of two glass series derived from the 45S5 Bioglass^® have been studied. The multinuclear ²⁹Si, ³¹P, and ²³Na solid‐state MAS NMR spectra of the glasses, Raman spectroscopy and the determination of some physical properties have generated insight into the structure of the glasses. The ²⁹Si MAS NMR spectra suggest that Nb⁵⁺ ions create cross‐links between several oxygen sites, breaking Si–O–Si bonds to form a range of polyhedra [Nb(OM)_6?y(OSi)_y], where 1 ≤ y ≤ 5 and M = Na, Ca, or P. The Raman spectra show that the Nb–O–P bonds would occur in the terminal sites. Adding Nb₂O₅ significantly increases the density and the stability against devitrification, as indicated by ΔT(T_x ? T_g). Bioglass particle dispersions prepared by incorporating up to 1.3 mol% Nb₂O₅ by replacing P₂O₅ or up to 1.0 mol% Nb₂O₅ by replacing SiO₂ in 45S5 Bioglass^® using deionized water or solutions buffered with HEPES showed a significant increase in the pH during the early steps of the reaction, compared using the rate and magnitude during the earliest stages of BG45S5 dissolution.     

High niobium oxide content in germanate glasses: Thermal,structural, and optical properties

Niobium alkali germanate glasses were synthesized by the melt‐quenching technique. The ternary system (90‐x)GeO₂–xNb₂O₅–10K₂O forms homogeneous glasses with x ranging from 0 to 20 mol%. Samples were investigated by DSC and XRD analysis, FTIR and Raman spectroscopy, and optical absorption. Structural and physical features are discussed in terms of Nb₂O₅ content. The niobium content increase in the glass network strongly modifies the thermal, structural and optical properties of alkali germanate glasses. DSC, Raman and FTIR analysis suggest niobium addition promotes NbO₆ groups insertion close to GeO₄ units of the glass network. XRD analysis also pointed out that samples containing high niobium oxide contents exhibit preferential niobium oxide‐rich phase after crystallization after heat treatment, which is similar to orthorhombic Nb₂O₅. Absorption spectra revealed high transmission range between 400 nm to 6.2 μm, added to a considerably decreased hydroxyl group content as the addition of niobium in the alkali germanate network. The niobium oxide‐rich phase crystallization process was studied and activation energy was determined, as well as nucleation and crystal growth temperatures and time for obtaining transparent glass‐ceramics.     

Optimized structural and mechanical properties of borophosphate glass

A series of phosphate glasses composed of (65-x)P₂O₅–15BaO–5Al₂O₃–5ZnO–10Na₂O-xB₂O₃ (x = 0, 2, 4, 6, and 8 mol%) were successfully prepared using the melt-quenching method. The effects of the addition of boron trioxide (B₂O₃) on the physical, structural, and mechanical properties of the glasses were investigated. As the added content of B₂O₃ increased from 0 to 6 mol%, the glass exhibited increased density and transition temperature, and decreased molar volume, indicating optimization of the glass stability. Raman spectroscopy revealed that the introduction of B₂O₃ transformed the glass from a chain structure to a three-dimensional network structure, which enhanced the chemical stability of the glass by the cross-linking of long phosphate chains with boron ions. Regarding the mechanical properties, when the boron content was 6 mol%, the flexural strength of the glass was 41% higher than that of the undoped boron, while the Vickers hardness and Knoop hardness values increased by 20.58% and 7.05%, respectively, and the fracture toughness was slightly decreased. In general, improving the mechanical properties of phosphate glass is of great significance for increasing the applications of this glass.     

Optical properties,thermal stability,and forming region of high refractive index La2O3–TiO2–Nb2O5 glasses

The high refractive index La₂O₃–TiO₂–Nb₂O₅ glasses were prepared by containerless processing, and the glass‐forming region was determined. The refractive index showed the range from 2.20 to 2.32, and the values were much higher than those of most optical glasses. The completely miscible 30LaO_3/2–(70?x)TiO₂–xNbO_5/2 (0 ≤ x ≤70) system was fabricated to study the compositional dependence of refractive index and optical transmittance. The crucial determinants of the refractive index of oxide glasses, oxygen molar volume, and electronic polarizability of oxygen ions were calculated. The principle of additivity of glass properties was suitable for the calculation of refractive index between glass and compositional oxides. All the glasses were colorless and transparent in the visible to 6.5 μm middle infrared (MIR) region. These results are useful for designing new optical glasses with high refractive index and low wavelength dispersion in wide optical window.     

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.     

Structure and properties of high Li2O-containing aluminophosphate glasses

The present study reports on the characterisation of the structure and properties of 50Li₂O·xAl₂O₃·(50 ? x)P₂O₅ glasses. The objective of the work has been to study the influence of the alumina content on the properties of lithium phosphate glasses, and the room temperature ionic conductivity in particular, with potential application as solid electrolytes in lithium secondary batteries. The glass formation domain has been also determined, proving that Al₂O₃ can be introduced only up to 5 mol%. The addition of alumina results in the increase of the glass transition temperature and decrease of the molar volume of the glasses. Furthermore, both chemical durability and room temperature conductivity increase as a function of the alumina content. The structure of the glasses has been followed by means of Fourier-transformed infrared spectroscopy (FTIR) and NMR spectroscopy, which has been used to establish the structure–properties relationship.     

Fabrication of Sr0.5Ba0.5Nb2O6 Nanocrystallite‐Precipitated Transparent Phosphate Glass‐Ceramics

Transparent (Sr_0.5Ba_0.5)Nb₂O₆ (SBN50) nanocrystallite‐precipitated phosphate glass‐ceramics were prepared by a conventional glass‐ceramic process. x(SrO–BaO–2Nb₂O₅) ? (100–4x)P₂O₅ (xSBNP) glasses with a refractive index of 1.9–2.0 exhibited high water resistance owing to the presence of Q⁰ and Q¹ phosphate units. Both bulk and surface crystallization of the SBN50 phase were observed in 20SBNP and 21SBNP glass‐ceramics. Although the nominal content of SBN50 crystals in the 21SBNP glass was larger than that in the 20SBNP glass, the latter exhibited better crystallinity of SBN50 and a higher number density of precipitated SBN nanocrystallites. By tuning the two‐step heat‐treatment and the chemical composition, transparent SBN50‐precipitated glass‐ceramics were successfully obtained. Given that no remarkable increase of the relative dielectric constants was observed after crystallization of the SBN50 nanocrystallites, it is postulated that the relative dielectric constant of the bulk is mainly governed by the amorphous phosphate region, and that the contribution of precipitation of the SBN50 nanocrystallites to the dielectric constant is not very significant in this system.     

Thermal,Structural, and Crystallization Properties of New Tantalum Alkali‐Germanate Glasses

In this work, new glass compositions were prepared in the ternary system GeO₂–K₂O–Ta₂O₅. Potassium oxide was added to reach the complete melt of the starting mixture and two composition series were investigated: the first one with a constant K₂O molar content of 10% in the ternary system (90–x)GeO₂–10K₂O–xTa₂O₅ and the second one with the same molar content of K₂O and Ta₂O₅ in the ternary system (100–2x)GeO₂–xK₂O–xTa₂O₅. Homogeneous and transparent glasses could be obtained between x = 0 and 20. X‐ray diffraction analyzes of samples with x = 25 identified orthorhombic Ta₂O₅ in the first series and an isostructure of K_3.8Ge₃Nb₅O_20.4 in the second series where it is assumed that Ta⁵⁺ ions are inserted in the Nb⁵⁺ sites. As one of our goal with these materials is related with the preparation of glass‐ceramics containing Ta₂O₅ nanocrystals, the first series has been selected for further characterizations. An increase in glass‐transition temperatures with increasing Ta₂O₅ content as well as an increase of the thermal stability from x = 0 to 10 has been identified by differential scanning calorimetry. For higher contents, crystallization events were identified. Fourier transform infrared and Raman spectroscopic characterizations allowed to point out the intermediary behavior of Ta₂O₅ in the vitreous network where TaO₆ octahedra are inserted inside the germanate network with TaO₆ clusters identified at higher Ta₂O₅ contents. Heat‐treated samples with high tantalum contents (x = 15 and 20) exhibit preferential precipitation of orthorhombic Ta₂O₅ with nanometric size, suggesting the possibility of obtaining transparent glass‐ceramics for optical applications.     

Structural and Textural Modifications of Ternary Phosphate Glasses by Thermal Treatment

Phosphate-based glasses of composition xNa₂O−(45+(10−x))CaO−45P₂O₅ with different Na₂O, CaO (x = 1, 5, 10, 15, and 20 mol%), and invariable P₂O₅ (45 mol%) contents were prepared using the rapid melt quench technique. The obtained thermal data from differential thermal analysis revealed a decline in glass transition (T_g) and crystallization (T_c) temperatures of glasses against the compositional changes. The inclusion of Na₂O at the cost of CaO in the glass network led to a reduction in its thermal stability. The thermal treatment carried out on glasses helped to derive their glass-ceramic counterparts. The amorphous and crystalline features of samples were characterized using X-ray diffraction patterns. The crystalline species that emerged out of the calcium phosphate phases confirmed the dominance of Q¹ and Q² structural distributions in the investigated glass-ceramics. The obtained scanning electron micrographs and atomic force microscopic images confirmed the surface crystallization and textural modification of the samples after thermal treatment. The N₂-adsorption–desorption studies explored the reduction of porous structures due to thermal treatment on the melt-driven glass surface. The measured elastic moduli and Vicker's hardness values of the glasses showed an increase after thermal treatment, which were reduced against the inclusion of alkali content in both glass and glass-ceramics.     

Role of MgO on the HAp forming ability in phosphate based glasses

Phosphate-based glasses 45P₂O₅–30CaO–(25 ? x)Na₂O–xMgO for different compositions of x = 0, 1, 2.5, 5 and 10 mol% were prepared using the normal melt quench technique. To study the influence of MgO on phosphate glasses, a series of experimental analyses such as ultrasonic velocities, differential thermal analysis, X-ray diffraction, energy-dispersive X-ray spectroscopy, pH measurements, Fourier transform infrared spectroscopy, scanning electron microscopy and in vitro studies were carried out in all the prepared glasses. A maxima in ultrasonic parameters at x = 2.5 mol% of MgO content and a further decrease in the same with the addition of MgO content were observed in all glasses. The observed results indicate that structural compactness of glass network took place up to 2.5 mol% of MgO (PCNM2.5), beyond which a loose packing of atoms led to structural softening in glass network. The results obtained from X-ray diffraction, Fourier transform infrared spectroscopy and scanning electron microscopy analyses in all glasses before and after in vitro studies revealed the existence of higher HAp-forming ability in PCNM2.5 glass.     

Novel insights into electrical transport mechanism in ionic‐polaronic glasses

Transformation of electrical transport from ionic to polaronic in glasses, which are a potential class of new cathode materials, has been investigated in four series containing WO₃/MoO₃ and Li⁺/Na⁺ ions, namely: xWO₃–(30?0.5x)Li₂O–(30?0.5x)ZnO–40P₂O₅, xWO₃–(30?0.5x)Na₂O–(30.5x)ZnO–40P₂O₅, xMoO₃–(30?0.5x)Li₂O–(30?0.5x)ZnO–40P₂O₅, and xMoO₃–(30?0.5x)Na₂O–(30?0.5x)ZnO–40P₂O₅, 0 ≤ x ≤ 60, (mol%). This study reports a detailed analysis of the role of structural modifications and its implications on the origin of electrical transport in these mixed ionic‐polaron glasses. Raman spectra show the clustering of WO₆ units by the formation of W–O–W bonds in glasses with high WO₃ content while the coexistence of MoO₄ and MoO₆ units is evidenced in glasses containing MoO₃ with no clustering of MoO₆ octahedra. Consequently, DC conductivity of tungstate glasses with either Li⁺ or Na⁺ exhibits a transition from ionic to polaronic showing a minimum at about 20‐30 mol% of WO₃ as a result of ion‐polaron interactions followed by a sharp increase for six orders of magnitude as WO₃ content increases. The formation of WO₆ clusters involved in W‐O‐W linkages for tungsten glasses plays a key role in significant increase in DC conductivity. On the other hand, DC conductivity is almost constant for glasses containing MoO₃ suggesting an independent ionic and polaronic transport pathways for glasses containing 10‐50 mol% of MoO₃.     

Effect of Ta2O5 Substituting on Thermal and Optical Properties of High Refractive Index La2O3–Nb2O5 Glass System Prepared by Aerodynamic Levitation Method

High refractive index glasses with nominal composition of 0.35La₂O₃–(0.65?x)Nb₂O₅–xTa₂O₅ (x ≤ 0.35) were prepared by aerodynamic levitation method. The effect of Ta₂O₅ substituting on their thermal and optical properties was investigated. All the glasses obtained were colorless and transparent. Differential thermal analyzer results show that as the content of Ta₂O₅ increased, the thermal stability of the glasses increased but the glass‐forming ability decreased. The transmittance spectra of all the obtained glasses exhibited a wide transmittance window ranging from 380 to 5500 nm. As the content of Ta₂O₅ increased, the refractive index of the glasses was enhanced from 2.15 to 2.21 and the dispersion was reduced with the Abbe number increasing from 20 to 27.     

Role of vanadium oxide on the lithium silicate glass structure and properties

The structural role of V in 28Li₂O–72SiO₂ (in mol%) lithium silicate glass doped with 0.5 mol% V₂O₅ was assessed using ²⁹Si and ⁵¹V Nuclear Magnetic Resonance (NMR), Fourier-transform infrared (FTIR), and X-ray photoelectron (XPS) spectroscopy techniques. Despite the low amount of V₂O₅ used, the structural information obtained or deduced from the statistical analysis of the NMR data could explain the evolution of glass properties after V₂O₅ addition. The XPS results indicated that all vanadium exists in 5+ oxidation state. Both the ²⁹Si NMR and FTIR data point toward an increase in the polymerization of the silicate network, caused by the V₂O₅ acting as network former, capable to form various tetrahedral units (for n = 0, 1, and 2) in the glasses. These units, which are similar to phosphate units, scavenge the Li⁺ ions and cause the silicate network to polymerize. However, in an overall balance, the entire glass network is depolymerized due to the additional nonbridging oxygens contributed by the vanadium polyhedra. The addition of vanadium causes the network to expand and increases the ionic conductivity.     

Ionic conductivity of Li2O–P2O5 glasses from thermodynamic modeling of their chemical structure

Modeling the transport properties of glasses, and ionic conductivity in particular, has been a recurrent issue motivated for their high interest in the rapid developing field of energy conversion and storage devices for a wide range of applications such as in lithium rechargeable batteries. Despite the absolute conductivity of phosphate-based glasses is not among the highest, their ease of preparation and ability to host transition metals and secondary anions has contributed to foster their research from which good examples are the LiPON electrolytes or the LATP-based glass ceramics. In this work, the structure and ionic conductivity of lithium phosphate glasses with nominal composition Li₂O⋅()P₂O₅, and x between 46 and 58 mol%, have been studied through the thermodynamic approach of the associated solutions model that was introduced by Shakhmatkin and Vedishcheva in glasses. The weak electrolyte model and the Anderson and Stuart model have also been employed herein in order to calculate the activation energy of the conduction of lithium ions within the glass matrix. Experimental ionic conductivity and activation energy data have been determined and were compared with the ones calculated using the models mentioned above. The structural units of the network have also been obtained by means of the thermodynamic approach and compared with those determined by ³¹P nuclear magnetic resonance (NMR) spectra. All of them showed that the glass network structure can be reliably represented by a solution of chemical species and whose properties can then be derived from the respective weights in the system.     

Structural and Optical Properties of Erbium and Ytterbium Codoped Germanoniobophosphate Glasses

A series of glasses with compositions of 20Na₂O–30Nb₂O₅–(5?y?z)Al₂O₃–30P₂O₅–(15?x)TiO₂–xGeO₂–yEr₂O₃–zYb₂O₃, where x = (0; 5; 10; 15), y = (0; 1), z = (0; 2) mol%, were investigated with respect to their structural, optical, and luminescence properties. The coordination of the germanium(IV) ion is normally reported as being mainly tetrahedral. However, results of this study suggest that the germanium(IV) ion may have an octahedral coordination and that TiO₂ is substituted. This proposition can be done mainly by ³¹P MAS‐NMR spectroscopy, which spectra show predominantly pyrophosphate chains in the different glasses, without changes in their polymerization after substitution. A similar coordination of germanium can also be identified by the photoluminescence behavior of the different codoped samples, which shows similar erbium(III) emission decay lifetimes (5 ms), and Judd–Ofelt intensity parameters. It was found that the upconversion emission process involved 1.5 photons. Regarding the thermal behavior, it is noted that the glasses containing higher proportions of GeO₂ exhibit higher thermal stability and are therefore more resistant to devitrification when compared to compositions containing more TiO₂.     

High Na‐ion conducting Na1+x[SnxGe2−x(PO4)3] glass‐ceramic electrolytes: Structural and electrochemical impedance studies

Na‐ion conducting Na_1+x[Sn_xGe_2?x(PO₄)₃] (x = 0, 0.25, 0.5, and 0.75 mol%) glass samples with NASICON‐type phase were synthesized by the melt quenching method and glass‐ceramics were formed by heat treating the precursor glasses at their crystallization temperatures. XRD traces exhibit formation of most stable crystalline phase NaGe₂(PO₄)₃ (ICSD‐164019) with trigonal structure. Structural illustration of sodium germanium phosphate [NaGe₂(PO₄)₃] displays that each germanium is surrounded by 6 oxygen atom showing octahedral symmetry (GeO₆) and phosphorous with 4 oxygen atoms showing tetrahedral symmetry (PO₄). The highest bulk Na⁺ ion conductivities and lowest activation energy for conduction were achieved to be 8.39 × 10^?05 S/cm and 0.52 eV for the optimum substitution levels (x = 0.5 mol%, Na_1.5[Sn_0.5Ge_1.5(PO₄)₃]) of tetrahedral Ge⁴⁺ ions by Sn⁴⁺ on Na–Ge–P network. CV studies of the best conducting Na_1.5[Sn_0.5Ge_1.5(PO₄)₃] glass‐ceramic electrolyte possesses a wide electrochemical window of 6 V. The structural and EIS studies of these glass‐ceramic electrolyte samples were monitored in light of the substitution of Ge by its larger homologue Sn.     

Enhanced photoluminescence quantum yield of Ce3+-doped aluminum–silicate glasses for scintillation application

Ce³⁺-doped 20Gd₂O₃–20Al₂O₃–60SiO₂ (GAS:xCe³⁺) glasses (x = 0.3, 0.7, 1.1, 1.5, 1.9 mol%) with Si₃N₄ as a reducing agent were prepared. The density of the glasses is around 4.2 g/cm³. With the increase in the Ce³⁺ concentration, both the photoluminescence (PL) and PL excitation peaks of GAS:xCe³⁺ glasses show a redshift because the 4f–5d energy levels of Ce³⁺ ions are narrowed. PL quantum yield and PL decay time of GAS:xCe³⁺ glasses are 28.32–50.59% and 43–64 ns, respectively. In addition, they both first increases and then decreases with the Ce³⁺ concentration increasing, reached the maximum when x = 1.1 mol%. The integrated X-ray excited luminescence (XEL) intensity of the GAS:1.1Ce³⁺ glass is 23.86% of that of Bi₄Ge₃O₁₂ (BGO) crystal, and the light yield reaches 1200 ph/MeV with an energy resolution of 22.98% at 662 keV when exposed to γ-rays. The PL and XEL thermal activation energies of GAS:xCe³⁺ glasses are independent of Ce³⁺ ions concentration. Scintillating decay time of the glasses exhibits two components consisting of nanosecond and microsecond levels, and the scintillating decay time gradually decreases with the Ce³⁺ concentration increasing. The difference between PL and scintillating decay time is discussed regarding the different luminescent mechanisms.     

Effect of the Glass Structure on Emission of Rare‐Earth‐Doped Borate Glasses

A series of glasses composed of xB₂O₃–8Al₂O₃‐(90?x)Na₂O–R₂O₃ (x = 65, 70, 75, 80, 85; R = Dy³⁺, Tb³⁺, Sm³⁺) were prepared through melt‐quenching. Structural evolution was induced by varying the glass composition. Increasing the glass network former B₂O₃ enhanced the luminescence of rare‐earth ions, as observed in the emission spectra. The mechanism of the glass structural evolution was investigated by the NMR spectra analysis. The dispersant effect of the glass structure was believed to promote the better distribution of the rare‐earth ions in the matrix and reduced the concentration quenching between them. The relationship between the glass structure and its optical properties was established.