Physical ageing in Se94Sn6 glass induced by gamma irradiation

A differential scanning calorimeter (DSC) has been used to monitor the influence of high-energy Co60 gamma-irradiation on physical ageing in Se96Sn4 glass. It is observed that the relaxation process in the studied glass is slow after 1 and 3 years of natural storage, and can be highly accelerated by γ-irradiation. The glass transition temperature Tg and the endothermic peak area, which is directly related to the relaxation enthalpy Δh, were found to exhibit a remarkable change after irradiation and also during an additional natural storage for 6 months and 1 year of the irradiated Se96Sn4 glass. Tg value of γ-irradiated glass increases by 12 K; meanwhile, that of additional 6-months- and 1-year-stored glass Tg increases by 19 and 20 K in comparison to its counterpart of 1-year-aged non-irradiated sample. The same trend is also observed for Δh, which becomes 2.33, 3.61 and 3.65 times that of the 1-year-aged non-irradiated case, respectively, for γ-irradiated, additional 6-months- and 1-year-stored glass. These indications reveal that γ-irradiation activates the relaxation of the glass towards a state thermodynamically close to the equilibrium super-cooled liquid state.