Photoexpansion inAs2S3glass

Abstract

Mechanisms of photoexpansion in chalcogenide glasses have been studied in three respects. A detailed x-ray investigation of As 2 S 3 shows that the photoexpansion can be connected with asymmetric broadening of the first sharp diffraction peak. Comparison between radiation-induced volume changes and density ratios of glassyto-crystalline forms in As 2 S 3 and SiO 2 implies that As 2 S 3 can expand since the glass is as dense as its crystal. When As 2 S 3 is exposed to illumination, the photoexpansion appears earlier and later than the photodarkening for bandgap and subbandgap illumination, respectively. These observations are discussed from a microscopic point of view. ͓S0163-1829͑98͒09209-1͔

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