Physical ageing effects in vitreous arsenic selenides

Effects of long-term physical ageing (∼20 years) studied in vitreous arsenic selenides using differential scanning calorimetry are compared with conventional short-term physical ageing (up to 1 year). It is shown that these effects differ not only by their amplitudes (increase in glass transition temperature and endothermic peak area near the glass transition), but also by compositional dependences. These results clearly testify in a favour of sufficient difference in microstructural origin for short- and long-term physical ageing in chalcogenide glasses.