Properties and Structure of Lead Halosilicate Glasses

The glass transformation temperature, thermal expansion coefficient, dc electrical conductivity, and IR transmission have been measured for four series of lead halosilicate glasses of the general composition (65– x )PbO· x PbX₂·35 SiO₂ (X=F, Cl, Br, I). Although results of these and other measurements suggest that the halide ions play similar structural roles in the glass, there appear to be significant differences in physical property behavior between glasses containing F⁻ anions and those containing the other three halide anions. These results are explained by a proposed model incorporating both bridging and nonbridging halide species.     

Infrared Absorption Coefficients of Silica Glasses

The absorption coefficient values of several silicate glasses in the IR radiation range were determined. Four methods were employed in this study: (1) direct transmission by CO₂ laser, (2) direct transmission through ultrathin sections using an IR spectrometer, (3) glass particle dispersions in KBr pressed pellets, and (4) IR reflection spectral analysis. Wide variations in values were observed for some of these techniques. The reasons for the variations were explored, and evidence is presented to support the conclusion that the reflection measurements and the low-power transmission technique yield accurate values. The pellet technique was found to possess too many experimental variables which could not be controlled and gave erroneous data. The damage produced by direct transmission of high-power radiation was severe and introduced effects which gave spurious results.     

卤化银光致变色玻璃

本文介绍了卤化银光致变色玻璃的研究现状。探讨玻璃组成,热处理,分相和卤光银相的尺寸和结构之间的关系及它们对光色性的影响。     

Physical Properties and Structure of Silica-Alumina-Europium Oxide Glasses

SiO₂–Al₂O3–Eu₂O₃ glasses were prepared for the composition 50siO₂·(50 – x )Al₂O_3·xEu₂O₃, and their density, sound velocity, and elastic modulus were measured. The chemical shift of the AIK a band emission spectra and the isomer shift of ¹⁵¹Eu by Mössbauer effect were obtained to determine the coordination states of Al³⁺ and Eu³⁺ ions in these glasses. It was found that the coordination number of Eu³⁺ ions was 12 and that the average coordination number of A1³⁺ ions was almost 5 in these glasses. By introducing Eu₂O₃, the packing of constituent ions was strongly enhanced and the elastic modulus increased in this system. The compositional dependence of the molar volume and elastic modulus were explained by these states of high coordination number for Eu³⁺ and low coordination number for Al³⁺ ions compared with those in the corresponding M₂O₃ crystals.     

铋掺杂锗酸盐玻璃超宽带近红外发光性质及机理

采用传统的高温熔融法制备了80GeO2–20RO (R=Ca, Sr, Ba)掺铋锗酸盐玻璃。研究了铋掺杂锗酸盐玻璃超宽带近红外发光性质,探讨了铋离子掺杂玻璃超宽带发光机理。结果表明：在808 nm激光激发下,铋掺杂锗酸盐玻璃随着碱土金属离子半径增加,中心波长为1300 nm的发射强度逐渐降低;在690 nm激光激发下,铋掺杂锗酸盐玻璃的近红外发射覆盖从900 nm到2000 nm波段但不呈现正态分布,荧光半高宽达428 nm。随着碱土金属离子半径的增加,其近红外发射中心位置逐渐向长波方向移动,推测近红外发光可能源于两种不同形式铋的发光中心。铋掺杂的锗酸盐玻璃具有良好的光学性能,较宽的荧光半高宽,将成为未来超宽带光纤放大器的增益介质。     

Spectroscopic Analysis of the Structure and Properties of Alkali Tellurite Glasses

Structural development of tellurite glasses with the addition of Li₂O and Na₂O has been studied using infrared, Raman, and X-ray photoelectron spectroscopies. The increase in intensity of the peak at 755 cm⁻¹ in the infrared spectra as compared to the peak at 620 cm ⁻¹ suggests the transformation of TeO₄ building units to TeO₃ pyramids with the addition of alkali oxide. Proposed structural change is further supported by the strong compositional dependence of the 755-cm⁻¹ peak in the Raman spectra as well as by the formation of a shoulder in the O 1 s peak of X-ray photoelectron spectra. In contrast to alkali silicate glasses, formation of nonbridging oxygens with the addition of alkali oxide is not observed.     

Y—La—Si—O—N系统氧氮玻璃形成与性能

本研究利用溶胶－凝胶技术制备Ｙ－Ｌａ－Ｓｉ－Ｏ－Ｎ氧氮玻璃配合料，在１大气压Ｎ２气氛中１６００℃左右温度熔制，制备出表观呈灰黑色透明的Ｙ－Ｌａ－Ｓｉ－Ｏ－Ｎ系统氧氮玻璃。实验结果表明氧氮玻璃含氮量为６．７－１０．９ａｔ％；显微硬度Ｈｖ为３．５－６．４７ＧＰａ；断裂韧性为０．６４－１．３８ＭＰａｍ＾１／２，Ｔｇ在１０００℃以上，膨胀系数为１．０５×１０＾－６℃＾－１．     

Thermally Stimulated Polarization and Depolarization in Halogen-Containing Lead Silicate Glasses

Thermally stimulated polarization and depolarization current (TSPC/TSDC) measurements were made on lead halide silicate glasses having compositions (65 − x )PbO· x PbX₂·35SiO₂ where x = 0, 0.1, 2, 10 and X = F, CI, Br, and I. The addition of halogen ions to lead silicate glasses gives rise to a new high-temperature TSDC peak in the vicinity of the peak previously observed in binary lead silicate glasses. The integrated area of the new peak is dependent on the amount and type of halogen ion present in the glass and does not saturate in the temperature range of our measurements. This new peak is attributed to space charge polarization of halogen ions.     

Physical Properties of Chalcogenide and Chalcohalide Glasses

The physical properties of glasses in the Ge₃₀As₁₀Se_{(60— x )}Te _x system with x = 25, 28, 30, and 35 at.% Te, the Ge₃₀As₁₀Se₃₀Te_{(30— y )}I _y system with y = 5, 10, 20, and 30 at.% I, the Ge₃₀As₁₀Se₃₅Te_{(25— z )}I _z system with z = 2, 6, 10, and 20 at.% I, and the [Ge₃₀As₁₀Se₃₀Te₃₀]_{(100— w )}I _w system with w = 0, 5, 10, and 20 at.% I have been investigated. The changes in the glass transition temperature, density, coefficient of thermal expansion, hardness, and viscosity are attributed to the delocalized metallic bonding character of Te in the substitution of Te for Se in the Ge-As-Se-Te glass system and the network-terminating role of iodine in the substitution of I for Te in the Ge-As-Se-Te-I glass system, respectively.     

Properties of Yttria-Aluminoborate Glasses

In the Y₂O₃–Al₂O₃–B₂O₃ system, homogeneous glasses were obtained from compositions containing from 50 to 65 mol% B₂O₃. The density, refractive index, and thermal expansion increase as Y₂O₃ replaces either B₂O₃ or Al₂O₃. These glasses have a dilatometric softening temperature above 665°, and below 300°C their dc electrical resistivity exceeds that of fused silica. The infrared absorption spectra indicate that BO₃, BO₄, and AlO₄, groups are present in these glasses.     

Effect of Sodium Halide on Micellar and Surface Properties of Cationic Silicone Surfactants

The effect of sodium halide on aggregation behavior of four cationic silicone surfactants, Si₃mamCl, Si₄mamCl, Si₄PyCl, and Si₄minCl, in solution was investigated using surface tension and conductivity measurements. The ability of sodium halide (NaCl, NaBr, and NaI) to reduce critical micelle concentration (CMC) values was in the order NaI > NaBr > NaCl. However, the γ_CMC values of the cationic silicone surfactants, Si₄mamCl, Si₄PyCl and Si₄minCl, in sodium halide solution are almost the same as those of the salt-free system. The values of and are negative, indicating that the micellization process and adsorption of the four cationic silicone surfactants at the air-solution interface are spontaneous.     

Structure of Sodium Aluminosilicate Glasses

A series of sodium aluminosilicate glasses composed of varying ratios ( R ) of Al₂O₃/Na₂O (0.25 R 2.0) has been simulated with the molecular dynamics technique using a tetrahedral form of a three-body interaction potential. Extrema in the activation energies for sodium diffusion and in the diffusion constants for all of the atomic species were observed for glasses with equal concentrations of Al₂O₃ and Na₂O ( R = 1.0). These changes corresponded to the minimum observed experimentally in the activation energy for electrical conductivity and to the maximum observed in the viscosity for glasses with compositions of R = 1.0. The coordination of aluminum remained 4 over the entire compositional range, negating the need to invoke a coordination change of aluminum to explain the changes in the physical properties. The changes to the simulated physical properties as R passed through the equivalence point were attributed to the elimination of nonbridging oxygen, to the introduction of oxygen triclusters, and to changes in the distribution of ring structures within the glass networks.     

Infrared Spectroscopy of Lead and Alkaline-Earth Aluminosilicate Glasses

Infrared spectroscopic studies of lead and alkaline-earth aluminosilicate glasses in the series x MO- x Al₂O₃ (1 - 2 x )SiO₂ M = Mg, Ca, Sr, Ba, and Pb; 0.05 x 0.275] were carried out in the range 2000 to 200 cm⁻¹. Three major absorption bands were observed in the 1100-, 800-, and 500-cm⁻¹ regions. The frequency and the intensity of the 1100-cm⁻¹ band varied linearly with composition. For a specific value of x , the changes in the frequency, intensity, and bandwidth of this band decreased in the order Mg > Ca > Sr > Pb > Ba and the apparent disorder in the glass structure, effected by the substitution of aluminum, increased in the direction Mg < Ca < Sr < Ba, with Pb in between Mg and Ca. The force constants and the bond orders of the Si-O and Al-O stretching vibrations in each of the glasses increased monotonically as Al/(Al + Si) decreased.     

Formation and Properties of Calcia-Calcium Fluoride-Alumina Glasses

The glass formation region has been determined for the CaO-CaF₂-Al₂O₃ ternary system. The glass transformation temperature of these glasses decreases as the CaF₂ concentration increases, whereas the thermal expansion coefficient and electrical conductivity increase. MAS-NMR (magic-angle-spinning nuclear magnetic resonance) indicates that the aluminum ions in these glasses are in tetrahedral coordination. The structures of these glasses are proposed to be analogous to those of similar silicate glasses, with aluminum ions replacing silicon ions and fluorine acting as a nonbridging anion.     

Elastic Properties of Alkali Phosphomolybdate Glasses

Ultrasonic velocities at 10 MHz have been measured in two series of lithium, sodium, and potassium phosphomolybdate glasses with two fixed P₂O₅ concentrations. Elastic moduli, Poisson's ratio, and Debye temperature have been calculated. The composition dependence of most of the properties of lithium glasses exhibits a trend opposite to that of potassium glasses. Properties of sodium glasses lie between the other two alkali systems. Alkali oxide modification is suggested to be accompanied by ring reformation in lithium and sodium glasses. Ring size effects have been shown to account for all of the composition dependence.     

Optical Properties of Silver Halide Photochromic Glasses Doped with Cobalt Oxide

Photochromic glasses having composition (SiO₂)₄₅(B₂ O ₃)₃₅(Al₂O₃)_7.5(Na₂O)_12.5(AgBr), (Cu₂O) doped with (CoO) _x , in which, x = 0, 0.006, 0.02 and 0.07 g were prepared using the conventional melt technique. The amorphous nature of these glass samples was confirmed using X-ray diffraction analysis at room temperature. The absorption measurements in the infrared region of the spectrum were recorded in the wave number range (4000–400) cm^?1. Spectral reflectance and transmittance at normal incidence of the prepared glass samples were recorded with a spectrophotometer in the spectral range 200–2500 nm. Experimental and theoretical densities of the prepared glass samples were measured, calculated and compared. Analytical expressions were used to calculate the real and imaginary parts of the refractive indices. Dispersion parameters such as: single oscillator energy, dispersion energy, average oscillator wavelength, and Abbe’s number were deduced and compared. Absorption dispersion parameters such as: optical energy gap for direct and indirect transitions, Urbach energy and steepness parameter were calculated. Effects of doping with cobalt oxide CoO as a transition metal on linear and predicted nonlinear optical parameters were investigated and interpreted. Experimental results indicate that there is an optimum concentration of cobalt doping around 0.006 g. The optical band gap decreases with increasing doping and causes an increase in nonlinear optical parameters. Doping with cobalt oxide improves the linear and nonlinear optical properties of the prepared glasses.     

ZnO-B_2O_3-Bi_2O_3玻璃的结构性能研究

用传统熔融冷却法制备ZnO-B_2O_3-Bi_2O_3,系统玻璃,采用X射线衍射法和差热分析法研究了玻璃的结构和玻璃的特征温度T_g和T_f,测试了玻璃的密度、热膨胀系数和介电常数等性能。结果表明,在ZnO-B_2O_3-Bi_2O_3系统玻璃中,当用B_2O_3逐步取代Bi_2O_3时,玻璃的特征温度T_g和T_f呈现逐渐升高的趋势,玻璃热膨胀系数由11.13×10~(-6)/℃减小至6.22×10~(-6)/℃,玻璃的密度由5.920 g/cm~3减小至4.114 g/cm~3,同时,玻璃的介电常数也有一定程度的下降。     

部分稀土掺杂磷酸盐玻璃发光性质分析

磷酸盐玻璃中单掺杂镱（Yb）、铒（Er）、钕（Nd）等稀土元素,对其光谱特性,荧光寿命,低温特性等将产生重要影响。也会改善杂质对磷酸盐玻离性能的影响。     

Properties and Structure of Lanthanum Borate Glasses

Glass formation limits were determined for the lanthanum borate glasses. Stable immiscibility prevents the formation of clear glasses over the range 0 to 20 mol% La₂O₃, but excellent quality glasses could be formed between 20 and 28 mol% La₂O₃. Data are reported for the density, refractive index, thermal expansion coefficient, glass transformation and dilatometric softening temperatures, transformation range viscosity, helium permeability, and chemical durability of these glasses. A limited Raman and infrared spectroscopy study suggests that lanthanum plays a similar structural role in these glasses and in the related crystals.     

Properties and Structure of Lead Fluorosilicate Glasses

An extensive glass-forming region has been determined for the lead fluorosilicate system. These glasses have a very high anionic (fluorine) conductivity. The value of 2 x 10_-4ω_-1.cm_-1 at slightly less than 200°C found for one glass is the highest anionic conductivity reported to date in a glass. Glass transition temperatures, thermal expansion coefficients, and UV-visible spectra were also measured. Results of these measurements and melt-history studies will be discussed and related to a proposed structural model for the lead fluorosilicate glasses.