Influence of rare earth oxides on structure, dielectric properties and viscosity of alkali-free aluminoborosilicate glasses

Abstract

The effect of rare earth oxides (La2O3, Pr2O3, Gd2O3, and Yb2O3) on the structure, dielectric properties, and viscosity of alkali-free aluminoborosilicate glasses was systematic studied. The results showed that rare earth oxides as modifiers can provide free oxygen to promote the formation of [AlO4] and [BO4] on the one hand and the increase of non-bridging oxygen (Qn) in [SiO4] on the other hand. The addition of rare earth oxides to alkali-free aluminoborosilicate glass reduced the dielectric constant from 4.96 to 4.52–4.62, which could optimize the dielectric properties of the glass. The coefficient of thermal expansion (CTE) decreased, while glass transition temperature (Tg) and glass expansion softening point (Td) increased with the addition of rare earth oxides. The introduction of rare earth oxides in this work all decreased the viscosity, fiber drawing temperature and melting temperature, and narrow the working temperature range of alkali-free aluminoborosilicate glass, which is beneficial to the glass fiber melting and drawing process.