INTERRELATION BETWEEN GLASS TRANSITION AND REVERSIBLE PHOTOSTRUCTURAL CHANGE IN a-As2S3

Abstract The optical absorption edge has been observed to make a parallel shift to lower energy in a -As 2 S 3 as the glass transition temperature, T g , increases. The structural difference corresponding to different T g and reversible photostructural change give the same linear relation between the edge shift and the volume change. The saturated position of the edge after long time illumination or annealing is determined only by the condition of last treatment and is independent of previous history. These results suggest that both structural changes are of the same kind and that in the glass there exists an equilibrium state under illumination, if crystallization is avoided.