MECHANISM OF REVERSIBLE PHOTOINDUCED OPTICAL EFFECTS IN AMORPHOUS AS2S3

A mechanism of the photoinduced structural transformations in the amor phous As2S3 was studied using a differential IR-spectroscopy Fourier t echnique in the spectral region between 400 cm(-1) and 100 cm(-1). A s tage of the reversible photodarkening is realized in the amorphous As2 S3 after the first cycle of the photoexposure and thermoannealing. The corresponding destruction-polymerization reaction is in contrast to t he one obtained for irreversible changes. The whole scheme of the phot o- and thermoinduced transformations in the amorphous As2S3 system may be explained as a coordination defect of formation and annihilation. (C) 1997 Elsevier Science B.V.