Enthalpic relaxation of 25Na(2)O center dot xTiO(2)center dot(75-x)SiO2 glasses

The enthalpic relaxation of the title glasses, studied by differential scan ning calorimetry, is well described by a mathematical model based on the st retched exponential relaxation function with the relaxation time proportion al to the actual viscosity. The dependence of viscosity on temperature and the fictive temperature was expressed by Mazurin's approximation. The relax ation parameters obtained correlated significantly with the glass compositi on, indicating the changes in the structural of the TiO2 role near a TiO2 c ontent of 3-4 mol%.