Preparation and properties of oxynitride glasses made from 27R 2O · 20BaO · 3Al 2O 3 · 50P 2O 5 glass

Abstract

The preparation of oxynitride glasses, made by remelting 27R 2O · 20BaO · 3Al 2O 3 · 50P 2O 5 glasses in anhydrous ammonia vapor, is described. Depending upon the melting temperature, processing time, and alkali ion size, glasses containing up to ≈ 6 wt% nitrogen were prepared. The oxynitride glasses had a lower dissolution rate in deionized water and thermal expansion coefficient, but a higher dilatometric softening temperature, refractive index, and Vickers microhardness. Models for nitrogen dissolution are discussed and used to calculate the glass composition from the measured weight loss and analyzed nitrogen content.