Crystallization Kinetics of Lithia-Silica Glasses: Effect of Composition and Nucleating Agent

The kinetics of crystallization of a 25Li₂O · 75SiO₂ (wt%) glass doped with Pt, Cu, Au, TiO₂, and P₂O₅ were studied using nonisothermal techniques. The activation energy, E , and the frequency factor, v , for the overall crystallization process depended directly on the critical cooling rate for the glass formation, R_c , of these glasses. The crystallization kinetics of several other glasses in the lithia-silica system were also studied as a function of composition, critical cooling rate, and liquidus temperature, T_m. E and v for these glasses were more dependent on the liquidus temperature than on R_c .     

Color and Spectral Transmittance of Amber Bottle Glass

Because of increased interest in color uniformity among iron-sulfur amber bottle glasses, a study was undertaken of their color, their spectral transmittance, and the relationship of these properties. It was found that the psychophysical attributes of color (C.I.E. system) as computed from complete light-transmittance spectra can actually be estimated for iron-sulfur amber glasses with good accuracy from transmittance at only two suitable wave lengths, 550 and 650 mp. Transmittance at 550 mμ is closely correlated with brightness (C.I.E.) and thus is sufficient to characterize color intensity, which is the most important variable of color quality among commercial amber glasses. There is also fair correlation between transmittance at 550 mμ and transmittance in the ultraviolet. The latter is important in the avoidance of photochemical action on bottled products. Incidental to this work, the transmittances of a large number of glasses were compared with their iron and sulfur contents. Broadly speaking, it was found that transmittance at 550 mp decreases with increasing ferrous iron or with increasing sulfide content. However, this transmittance is affected substantially by other factors, such as gross composition, minor constituents like fluorine, and thermal history, of which no account was taken in the present work. Transmittance at 1050 mp can be correlated closely with ferrous iron content (as determined by chemical analysis) and absorbancy per unit concentration of ferrous iron in carbon-sulfur ambers is about the same as in green glasses containing no sulfur.     

新型氧氟化物玻璃的化学稳定性

对新型含碲氧氟化物玻璃在中性、碱性、酸性条件下的化学稳定性进行了研究。实验表明：水的侵蚀使玻璃表面形成碱性沉淀物．阻碍了侵蚀反应进一步发生,使在抗水实验中,质量损失并不随碲含量的增加而增加。对碱侵蚀后的样品用盐酸漂洗的实验显示,随氧化碲含量增加,玻璃化学稳定性变差;经碱腐蚀后,玻璃表面雾化,可见透过率明显减低。碱中浸泡后未用酸漂洗的样品在3100nm附近出现明显的水吸收峰;盐酸处理后,羟基吸收峰消失,但整体的中红外透过率下降。玻璃在酸性条件下侵蚀相同时间的质量损失是碱中的7倍．但由于是均匀腐蚀,侵蚀前后玻璃的可见红外透过率不变。     

Fluorochalcogenide glasses

A new variety of chalcogenide vitreous materials—fluorochalcogenide glasses—have been synthesized by the introduction of sodium, thallium, lead, manganese, and bismuth fluorides into the Ga₂S-GeS₂ system. These glasses are characterized by high glass transition temperatures (560–670 K), an optical transmittance up to 75% in the visible (from 0.48 μm) and IR (to 7.5 μm) spectral ranges, chemical durability in reactive acid media, low crystallization ability, and the stability of physicochemical and optical properties. Depending on the introduced fluoride, the glasses can be dielectrics, semiconductors, or ionic semiconductors. The spectral investigation of fluorochalcogenide glasses by using the X-ray emission, Raman, NMR, and EPR spectroscopy reveals the complex features of their structure. The metal cations form bonds with sulfur in different structural positions. The glass network providing the mobility of sodium ions is formed in sodium fluoride-containing glasses. The formation of groupings of the [≡Ga ← F-Ge≡] type is the main structural feature of fluorochalcogenide glasses.     

Fluorochalcogenide glasses

A new variety of chalcogenide vitreous materials—fluorochalcogenide glasses—have been synthesized by the introduction of sodium, thallium, lead, manganese, and bismuth fluorides into the Ga₂S-GeS₂ system. These glasses are characterized by high glass transition temperatures (560–670 K), an optical transmittance up to 75% in the visible (from 0.48 μm) and IR (to 7.5 μm) spectral ranges, chemical durability in reactive acid media, low crystallization ability, and the stability of physicochemical and optical properties. Depending on the introduced fluoride, the glasses can be dielectrics, semiconductors, or ionic semiconductors. The spectral investigation of fluorochalcogenide glasses by using the X-ray emission, Raman, NMR, and EPR spectroscopy reveals the complex features of their structure. The metal cations form bonds with sulfur in different structural positions. The glass network providing the mobility of sodium ions is formed in sodium fluoride-containing glasses. The formation of groupings of the [≡Ga ← F-Ge≡] type is the main structural feature of fluorochalcogenide glasses.     

谈玻璃配合料的密实

玻璃工业要达到文明生产、节能减排的目的,玻璃配合料的密实化是必需的,尤其是生产硼料、含铅料和乳浊料等玻璃制品时更为迫切。阐述了玻璃配合料密实的重要性,介绍了配合料密实常用的方法,国内外压块法研究概况,总结了压块法密实的技术要点。     

Towards highly transparent tungsten zinc sodium borate glasses for radiation shielding purposes

The impact of tungsten oxide (WO₃) additions on the structure, some physical and radiation shielding parameters of sodium zinc borate glasses have been scrutinized. These glasses were properly produced by the melt quenching method. The amorphous state was affirmed by X-ray diffraction (XRD) data. The internal structure within the short-range order of the glassy network was studied by the method of infrared spectroscopy (IR). The results of IR showed that the BO₄ units are transformed to BO₃ accompanied by the formation of nonbridging oxygens with further WO₃ doping. This transformation of BO₄ to BO₃ and nonbridging oxygens is employed to explain the increase in the molar volume values with changing WO₃/ZnO amount. Further, the optical transmittance was measured within the visible range to assure the transparency of the prepared glasses. The transmittance results confirm the absence of W⁵⁺, W⁴⁺, W³⁺ states; based on the absence of their absorption bands. Also, the transmittance results indicate that the only oxidation state in the present glasses is hexavalent tungsten (W⁶⁺). Additionally, the parameters of radiation protection of the manufactured glasses were investigated. It was found that, the addition of WO₃ improves not only the radiation protection parameters (such as the linear attenuation coefficient) but also the transparency of the prepared glasses. Finally, we concluded that, the addition of WO₃ to the glass samples leads to transparent glasses with an improved shielding ability at low energies but effects slightly at high energies. Due to the high transparency and the increased values of the linear attenuation coefficient of the prepared glasses, they are considered promising glasses in the field of nuclear radiation protection, especially at low energies.     

Gamma-Ray Shielding Effectiveness of Lead Bismuth Germanoborate Glasses

The gamma-ray shielding effectiveness of the lead bismuth germanoborate glasses has been studied. The mass attenuation coefficients (μ/ρ) of the selected glasses have been obtained through both XCOM program and MCNP5 simulation code. The (μ/ρ) values calculated in both methods are found to be in good agreement and these values are used to calculate effective atomic number, mean free path, half-value layer and energy exposure buildup factors. The shielding effectiveness of these samples has been compared with that of window glasses and some standard shielding concretes. The lower values of mean free path point to the fact that the selected glasses are efficient gamma shields.     

Laser-Induced Swelling of Borosilicate Glasses—An Analysis of Associated Microstructural Development

Borosilicate glass swelling by laser irradiation is an unusual phenomenon. The height of raised hemisphere on the swelled glass surface can be approximately 10–15% of the 1–3 mm glass thickness. To understand the mechanism of glass swelling, the micro-structural information of swelled glasses is essential. Several transmission electron microscopy (TEM) techniques, including bright field image (BFI), selected area electron diffraction (SAED), energy dispersive spectroscopy (EDS), and electron energy loss spectroscopy (EELS) analysis, were used to find out the possible microstructure changes of the swelled glasses. Transition metal nanoparticles or alkali metal segregations as well as gas bubbles in the swelled glasses were identified. These observations suggest that reduction of glass components may provide oxygen to form bubbles, which can increase in size due to thermal effects of the laser radiation and lead to the glass swelling.     

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.     

卤化银光色玻璃的光致变色动力学模型

以卤化银光色玻璃在发生光色过程中Ｘ＾－的电子逸出几率α和Ａｇ＾＋的电子俘获几率ｐ为基础,推导了卤化银光色玻璃的光致变色动力学模型。比较了Ｆ系列卤化银光色玻璃的理论的变色动力学曲线与实测的变色动力学曲线,并讨论了光致变色的速度与辐照时间的关系,最后探讨了饱和变暗透过率与５ｍｉｎ变暗透过率的差异。     

Hydrolytic resistance of K2O–PbO–SiO2 glasses in aqueous and high-humidity environments

Some historical glasses (lead-wood ash glasses, lead-crystal glasses…) are silicate glasses with high content of lead and potassium. This work presents the evaluation of the chemical stability of high-lead glasses in a high relative humidity atmosphere and as result of aqueous immersion. In both situations, the alteration mechanism begins with the lixiviation of alkali metal and lead ions, followed by the hydrolytic attack of the silica glass network. According to the results, the glasses with a higher content of lead show the fastest degradation due to their higher hygroscopicity. Environmental CO₂ can be dissolved in the adsorbed water and favor the formation of intermediate degradation compounds.     

Effect of halogen on imprinting gradient refractive index microstructure in GeS2–Ga2S3–NaX (X=F,Cl, Br,I) glasses for broadband infrared diffraction gratings

Chalcohalide glasses with a gradient refractive index (GRIN) microstructure were imprinted by microthermal poling for realizing diffractive optical elements covering the visible to middle-infrared wavelength range. The effect of halogen ions on the saturation poling voltage (U), surface profile, diffraction pattern, optical transmittance, GRIN microstructure, and structural rearrangement of poled glass is investigated. An effective imprinting formation region for a GRIN microstructure based on the U and glass composition is observed under fixed poling time and temperature. The onset U (60 V–150 V) and activation energy of mobile cations (0.449 eV–0.533 eV) decreases with the atomic number of the halogen from F to I, but the saturation diffractive order (8th to 11th levels) and phase difference (~0.08λ to 0.18λ) increases accordingly. The onset U and activation energy decrease with the deformability of the glass network and radius of the halogen ions. The phase difference and saturation diffractive orders decrease with the proportion and electronegativity of interval halogen atoms in the glass network. Thus, chalcohalide glasses with GRIN microstructures can be tailored by adjusting the type of halogen ions for realizing various diffraction optical elements.     

含铅玻璃及其无铅化的研究

介绍了铅对人体的危害,综述了一些为限制铅的使用及排放而制定的相关法规,详细介绍了铅玻璃在现阶段中的一些主要用途和目前人们对这些玻璃的无铅化方面的工作。指出电子产品无铅化的迫切性。     

Elaboration and characterisation of foam glass from cathode ray tubes

Abstract

Research into the recycling of electronics waste materials, such as cathode ray tubes (CRTs) and in particular their component glasses, is required by both French and European legislation. One possible solution to the problem of CRT glass waste is to convert it into foam glass, a material with very promising properties. Foam glasses can be prepared from CRT glasses containing heavy elements (lead, barium) through reaction with a reducing agent such as TiN or SiC. The present experimental study sought to determine the mechanism of foam glass formation and the structural differences between bulk and foam glasses. Additionally, the specific characteristics of bulk and foam glasses such as density, porosity, thermal and mechanical properties were determined, as well as their structural characteristics, using X-ray diffraction, differential scanning calorimetry, photoelectron spectroscopy and scanning electron microscopy with energy dispersive spectroscopy. The results indicate that reutilisation of CRT glass in the form of foam glass is a very promising recycling option.     

Preparation of transparent Bi2O3-ZnO-B2O3 glass by conventional sintering at low temperatures

Glass components fabricated by the sintering route have wide-ranging applications. However, one issue is that the crystallization tendency of glass powders often leads to residual pore-glass interfaces and crystal-glass interfaces, thereby causing strong light scattering and rendering the sintered glass opaque. This issue is particularly pronounced in glasses with a low glass transition temperature (T_g) due to their weak bonding and thus high crystallization tendency. In the present study, a Bi₂O₃-ZnO-B₂O₃ glass with a low T_g of 364°C was fabricated using the conventional sintering method to explore whether transparent glass materials can be obtained. The temperature range of crystallization of the glass powders was analyzed using differential scanning calorimetry. X-ray diffraction was employed to analyze the crystalline phases formed in the sintered glasses. The microstructure of the sintered glasses was examined using scanning electron microscopy. The optical transmittance of the sintered glasses was measured using ultraviolet-visible spectroscopy. The results show that transparent sintered glasses with the highest transmittance of 54% at the wavelength of 650 nm can be obtained by using a coarser initial particle size, lower forming pressure, and an appropriate sintering temperature/time (430°C/30 min). It is suggested that this combination of processing parameters can suppress glass crystallization while maintaining a low glass viscosity during sintering.     

A Simple and Highly Efficient Method for Synthesis of Ce3+‐Activated Borogermanate Scintillating Glasses in Air

Fast Ce³⁺‐activated borogermanate scintillating glasses with the density of 5.58–5.67 g/cm³ were synthesized by melt quenching method in air atmosphere for the first time. The optical transmittance and X‐ray absorption near edge spectroscopy results confirm that Ce⁴⁺ ions can be effectively reduced to Ce³⁺ ions by adding 0.31 mol% Si₃N₄ as a strong reducing agent during glass synthesis. The luminescence behavior under both ultraviolet and X‐ray excitations indicate that the proposed Ce³⁺‐activated borogermanate scintillating glasses have a broad emission band centered at 430 nm and a decay time of less than 25 ns. This will be of great interest in high‐energy physics and nuclear physics engineering.     

蓝宝石玻璃减反射膜的制备与性能

采用真空蒸发镀技术在蓝宝石玻璃单面和双面分别沉积了1层(MgF2)、2层(Al2O3-MgF2)和4层(Al2O3-H4-Al2O3-MgF2)减反射膜,讨论了极限温度、紫外光老化、腐蚀和摩擦对镀膜蓝宝石玻璃透过率的影响.结果表明,镀减反射膜后,蓝宝石玻璃的透过率得到提升,双面镀膜的透过率比单面镀膜高出6个百分点.经各...     

Interfacial Energy in Phase-Separated Glasses from Emulsion Rheology

Classical theories of emulsion rheology yield information on the deformation of a liquid drop dispersed into another liquid matrix phase. By connecting the deformation and relaxation, respectively, and the capillary number of the dispersed phase, interfacial energy can be estimated. This was applied to demixing borosilicate and lead borate glasses, which are known to exhibit significant form anisotropy after elongation. Interfacial energies in these two systems were calculated based on graphical data of prior isothermal elongation experiments. The method is discussed in terms of experimental difficulties. It might provide an alternative way to overcome the obvious lack of information on interfacial energies in glasses.