Polymer Mixtures in Na2O.Sb2O3.GeO2 Glasses

Abstract

Ternary Na2O.Sb2O3.GeO2 glasses (with various [Na]/[Na + Sb] ratios) that contained ≥65 mol% GeO2 were prepared. Their densities (volumes), refractive indices, and infrared spectra were determined and their colors noted. The ternary glasses with ≥88 mol% GeO2 exhibit nearly additive volumes, refractivities, and frequencies for the main Ge‐O vibration. Ternary glasses with lesser amounts of GeO2 exhibit a variety of behaviors, depending on the [Na]/[Na + Sb] ratio. Small amounts of Sb2O3 cause significant volume and refraction deviations, as well as changes in νGe‐O, that can be associated with gradual elimination of GeO6 octahedra. All the information supports a model for the glasses with 65 to 88 mol% GeO2 that involves a degree of depolymerization that is greater when Na2O and Sb2O3 are present together than when either is present alone.