Colossal photostructural changes in chalcogenide glasses. Athermal photoinduced polymerization in AsxS100-x bulk glasses revealed by near-bandgap Raman scattering

TL;DR

This study reveals a new athermal photoinduced polymerization process in AsxS100-x glasses using near-bandgap Raman scattering, showing significant structural changes involving sulfur rings and chains.

Contribution

It demonstrates a novel photoinduced polymerization effect in chalcogenide glasses, with a higher bond involvement than previously reported, advancing understanding of photostructural transformations.

Findings

Photoinduced polymerization involves S8 ring scission and chain formation.

Structural changes are athermal and induced by near-bandgap illumination.

Bond involvement in the effect is an order of magnitude higher than prior studies.

Abstract

Near-bandgap Raman scattering was used to induce and study photostructural changes in AsxS100-x bulk glasses revealing a new photoinduced polymerization effect. Raman spectra were recorded also in off-resonant conditions allowing for a detailed comparison between the equilibrium glass structure and the metastable one induced by illumination. It is shown that in S-rich glasses structural changes involve the athermal scission of S8 rings and their polymerization to Sn chains. The fraction of bonds involved in this effect is surprisingly high, being one order of magnitude higher than the corresponding fractions reported up to now in photostructural studies in chalcogenide glasses.