Photo- and thermo-stimulated structural relaxation in As–S glasses

•Dark and light-assisted physical aging is studied as a function of T in As–S glasses.•Temperature threshold of structural relaxation is observed.•Explanation is proposed on a basis of temperature-dependent constraint theory.

Homogeneous AsxS100 − x glasses (25 ≤ x ≤ 42) are investigated with conventional differential scanning calorimetry. Enthalpy losses during structural relaxation are determined for the glasses aged at different temperatures in the dark and under the exposure with 620 nm light. It is shown that light exposure accelerates structural relaxation in chalcogen-rich glasses, but does not modify the kinetics of As40S60 and As42S58 compositions. The results are analyzed from the temperature-dependent constraint theory point of view.