Chapter 4: Germanate Glasses Containing Only Glassformers Check Access

Germanate glasses containing SiO₂, B₂O₃, and/or P₂O₅ are formed by both traditional and non-traditional methods. Expressions for additivity of the properties of glasses are applied to the binary and ternary germanate glass systems containing only glassforming oxides. The densities and the log of the helium diffusivity and solubility of SiO₂–GeO₂ and B₂O₃–GeO₂ glasses are additive. The refractive indices and thermal expansion coefficients of SiO₂–GeO₂ glasses are also additive while those of the B₂O₃–GeO₂ glasses are not. The glass transformation temperature and transformation range viscosity of the B₂O₃–GeO₂ glasses are also additive. None of the properties of the P₂O₅–GeO₂ glasses display additivity. The densities and refractive indices of the ternary germanate glasses systems containing two other glassforming oxides can be reasonably approximated by additivity, although the values used for P₂O₅ are questionable. Reaction of hydrogen with SiO₂–GeO₂ glasses caused by either temperature increases or exposure to ionizing radiation results in the formation of large quantities of hydroxyl. The density of SiO₂–GeO₂ glasses also increases with ionizing radiation exposure.