Influence of aluminium oxide on the phase separation and electrical conduction in photochromic glasses

Abstract

The electrical resistivity for differently heat-treated photochromic glasses has been measured from 100°C to 300°C. No dependence of the electrical resistivity on the heat treatment (temperature or time) is found. It is concluded that phase separation takes place only locally around the silver colloid particles precipitated in the glass with heat treatment. The conducting continuous base glass is assumed to remain unchangeable with heat treatment. It is assumed that Al 2O 3 prevents the phase separation in glass, whereas the silver colloid particles activate this process. A new approach to the boron oxide anomaly is presented.