داریوش سوری

The glass transition temperature dependence to heating rate and therefore the activation energy (DHn ) of the glass transition of (60-x)V2O5–xNiO–40TeO2 oxide glasses with 0rxr20 (in mol%) were investigated at heating rates j (¼3 6, 9, 10 and 12 K/min) using differential scanning calorimetry (DSC). The heating rate dependence of Tg was used to investigate the applicability of different theoretical models describing the glass transition. Using the application of Moynihan and Kissinger et al. models to the present data, different values of (DHn ) at each different heating-rate regions were obtained. The fragility parameter (m¼DHn /RTg)was 24.98 for x¼10 mol%, suggesting that this glass may be considered as a rather strong glass (fragility index m420 is an indication of fragile glass). Also the compositional dependence of T and DHn was investigated.