Effect of physical ageing on the mechanical relaxation of a chalcogenide glass

The mechanical modulus and internal friction of As2 Se18, glass were measured in the temperature range 175-290K and frequency range 103-1 Hz. The results show that physical ageing at 293 K decreases the height of secondary relaxation peak by more than half its original value, and little change in the temperature dependence of the modulus occurs. The rates of secondary relaxation obtained from the isochronal and isothermal methods differ, due mainly to the rapid increase in the amplitude of relaxation with temperature.