The effect of gamma irradiation on glass transition temperature and thermal stability of Se 96Sn 4 chalcogenide glass
Se 96Sn 4 chalcogenide glass was prepared by melt quenching technique and exposed, at room temperature, to different doses of 4, 8, 12, 24 and 33 kGy of high-energy 60Co gamma irradiation. Differential scanning calorimeter (DSC) was used under non-isothermal condition to determine the glass transition temperature Tg, onset Tc and peak Tp temperatures of crystallization, of un-irradiated and γ-irradiated samples, at four different heating rates. The variation of Tg with heating rates was utilized to calculate the glass transition activation energy Et for un-irradiated and γ-irradiated glass, using the methods suggested by Kissinger and Moynihan. Based on the obtained values of the characteristic temperatures Tg, Tc and Tp, thermal stability was monitored through the calculation of the S parameter and the crystallization rate factor < Kp> for irradiated and un-irradiated glass. Results reveal that, as γ-dose increases Tg increases up to 12 kGy then decreases at higher doses but remains more than that of un-irradiated glass. Meanwhile, both Et and < Kp> attain their minimum values at the same dose of 12 kGy and the glass is thermally stable at this particular dose.