The Young's moduli of various oxide glasses (silicate, borate, phosphate, and tellurite) were measured using an ultrasonic method. To predict the Young's moduli of the oxide glass systems, empirical compositional parameters Gi and Vi, based on the Makishima‐Mackenzie theory, were obtained, where Gi is the dissociation energy and Vi the packing density parameter of a single‐component oxide. The relationship between the calculated Young's modulus from the compositional parameters and the measured Young's modulus was investigated. Experimental results indicated that the Young's modulus of phosphate and tellurite glasses could not be predicted using these parameters. Thus, it was necessary to modify the Gi, by considering P2O5 and TeO2 as glass network formers. As for the phosphate glass, it exhibited a layered structure that consisted of P=O double bond and three chains of P‐O bond. In this paper, the modified Gi of P2O5 was calculated using the assumption that the P=O double bond is a nonbridging bond and does not contribute to Young's modulus. In the case of tellurite glass, the glass structure is mainly composed of TeO4 trigonal pyramids, and the addition of other oxides results in structural changes to the TeO3 trigonal pyramid. However, the mechanisms of such structural changes have not yet been clarified. Therefore, the modified Gi of TeO2 was calculated from the measured value using the density and Young's modulus of pure TeO2 glass. The results revealed that the calculated values using our proposed parameter were in good agreement with measured values all through the oxide glasses.
The density of oxide glass including silicate, borate, phosphate, tellurite, and germanate glasses were measured using the Archimedes method. On the assumption that the ionic packing ratio is approximately a constant independent of chemical composition, an empirical equation for estimating the density from chemical composition was proposed. The calculated values are in reasonable agreement with the corresponding measured ones. I. IntroductionT HE density of glass is undoubtedly one of the most important properties in industrial glass production, and is required for calculating other properties, such as refractive index, elastic properties, and thermal conductivity. Academically, density, which is related to the molar volume and the ionic packing ratio, plays a significant role in the study of structure in materials, whether they are inorganic, polymeric, or metallic in nature.In the case of glass, the density depends almost entirely on chemical composition. Therefore, the problem of calculating the density according to their chemical composition has been the focus of much expert attention. 1-6 For example, Priven and Mazurin 1 compared various methods for the density estimation, reporting estimation errors of 0.038-0.11 g/cm 3 for glasses containing 450 mol% silica. Some important models were also summarized by Scholze (p. 204). 2 In 2007, Fluegel 3 performed a statistical analysis of the available silicate glass density data in SciGlass 7 and succeeded in reducing the density estimation errors provided by Priven and Mazurin. 1 Linard et al. 6 proposed a model to predict the density of complex molten borosilicate glass in the temperature range from 9001 to 13001C. Although these models make it possible to carry out calculations with a fairly high degree of accuracy, they are often valid only for glasses containing mainly silica.The purpose of this work is to propose a guideline in predicting the density from chemical composition. We systematically measured the density of silicate, borate, phosphate, tellurite, and germanate oxide glasses. The empirical equation for calculating the density from chemical composition is derived by use of this experimental result and the data from INTER-GLAD database. 8
Experimental results are presented on the neutron scintillating properties of a custom-designed Pr3+ (praseodymium)-doped lithium (Li) glass. Luminescence was observed at 278 nm wavelength, originating from the 5d-4f transition. Time-resolved measurements yielded about 20 ns decay times for ultraviolet and x-ray excitation while much faster decay times of about 6 ns were observed for alpha particle and neutron excitation. Actual time-of-flight data in laser fusion experiments at the GEKKO XII facility of the Institute of Laser Engineering, Osaka University reveal that it can clearly discriminate fusion neutrons from the much stronger x-rays signals. This material can promise improved accuracy in future scattered neutron diagnostics.
Accurate refractive indexes of oxide glasses—silica, silicate, borate, aluminate, tellurite, antimonate, and heavy metal gallate glasses—are presented in the wavelength range 0.265 to 1.710 μm. Factors affecting the refractive index dispersion are discussed by using the single‐oscillator Drude‐Voigt equation. The values of nd at 0.5876 μm are affected mainly by the average resonance wavelength at the ultraviolet region through all of the glass systems. The distinguishing features of borate glasses—relatively high refractive index and low dispersion—are related to the large number of molecules, N, in a unit volume, compared with those of the other glasses. The number N determined by density measurements is related to the fraction of the four‐coordinated borons estimated by Greenblatt and Bray.
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