Chapter 3: Vitreous GeO₂ Check Access

The properties of vitreous germania have been the subject of many studies, with significant differences among the published values. After discussion of the preparation of vitreous germania, methods for measuring a number of the glass and melt properties are presented, the quality of the data for many of these properties is evaluated, and “best values” are determined. Possible causes for the experimental scatter in these properties are discussed. Properties considered include the density, refractive index, thermal expansion coefficient, elastic moduli, electrical conductivity, sodium ion diffusivity, helium and neon diffusivity and solubility, temperature dependence of the heat capacity, glass transformation temperature, and the transformation range and melt viscosities. Determination of the fictive temperature and its effect on properties is considered. The fragility of vitreous germania is determined from the viscosity data. The effects of pressure and ionizing radiation on the density of vitreous germania are summarized. The reaction of vitreous germania with water vapor and hydrogen gas is discussed.