Preparation of Cathodochromic Sodalites

Abstract

Sodalites were prepared by both solid‐state and low‐temperature (80°C) hydrothermal reactions. Induction of cathodo‐chromism was studied and optimized. Undoped halide sodalites can be activated by firing in an oxidizing atmosphere. The coloration and optical bleaching sensitivities depend strongly on both the method of preparation and the activation treatment. The factors which determine the cathodochromic properties, e.g. bromine content, Al/Si ratio, and oxygen content, are discussed.