NEW IR-TRANSMITTING CHALCOHALIDE GLASSES

The glass-forming region in the GeS2-Ga-I system has been determined a nd its limits are 32 at.% Ga and 60 at.% I. The basic physicochemical parameters (glass transition temperature, density and microhardness) o f the glasses have been measured. They are transmitting in the mid IR- region up to approximately 20 mum. A photobleaching effect in thin fil ms has been observed, and a reversible shift of the optical absorption edge after combined treatment by thermal annealing and ultraviolet ex posure has been established.