Glass useful as either photosensitive glass or opaline foam glass

摘要

The invention relates to a photosensitive and heat-sensitive glass which is composed of 25-70 mol % of Al2O3 and/or Ga2O3, 30-75 mol % of at least one of CaO, BaO, SrO and MgO and 0-40 mol % of an auxiliary component which is at least one of SiO2, GeO2, B2O3 and P2O5. The glass is produced by melting a batch mixture of powdery raw materials. By exposure to UV rays the glass colors in yellowish brown, and the color does not fade by termination of the exposure. Bleaching of the colored glass is accomplished by heating for a short time at about 150 DEG -300 DEG C. Coloration and bleaching can be repeated without deterioration. The same glass turns into an opaline foam glass, which presents a very attractive appearance, by heat treatment at a temperature above the softening temperature. This change is irreversible. The foams created in the glass matrix are usually tens of microns in diameter.