Dariush Souri

Abstract The activation energy (DH* ) of the glass tran- sition and the heating-rate dependence of the glass transi- tion temperature (Tg)ofV2O5–Sb2O3–TeO2 glasses were determined using differential scanning calorimetry tech- nique. Non-isothermal measurements were performed at different heating rates u (=3, 6, 9, 10, 13 K/min). The heating rate dependence of Tg was used to investigate the applicability of different theoretical models describing the glass transition. The application of Moynihan and Kissinger et al. models to the present data led to different values of (DH* ) at each different heating-rate regions. This behavior was attributed to the strong heating rate depen- dence of the activation energy of the process. The fragility parameter (m = DH* /RTg) were [90, suggesting that these glasses may be classified as strong glasses. The vis- cosity, g, calculated at a few selected temperatures near the glass transition region increased with increasing Sb2O3 content at any given temperature, which is also expected. Also the compositional dependence of Tg and DH* was investigated.