Devitrification of High‐SiO ₂ Glasses of the System Al ₂ O ₃ ‐SiO ₂

Abstract

Pertinent works of previous investigators are reviewed briefly. A superior technique for the preparation of experimental glasses of high purity and chemical homogeneity is presented. Devitrification growth‐rate data and traction‐viscosity data are reported for high‐silica glasses of the system Al 2 O 3 ‐SiO 2 . Glasses with added Al 2 O 3 were found to devitrify to cristobalite more rapidly than ultrapure silica glasses at a given temperature, and yet their fluidities (i.e., reciprocal viscosities) were found to be less. The devitrification growth rate, g, was found to be of zero order and to follow the temperature dependence In( g/T ) = ‐(B/T) + In A over the temperature range 1561°K. T 1730°K.