STRUCTURAL RELAXATION OF BARIUM CRYSTAL GLASS

Structural relaxation of barium crystal glass contemporary produced by RONA glassworks was described by Tool-Narayanaswany-Mazurin (TNMa) model. The distribution of relaxation times was expressed by empirical Kohlrausch Williams Walls relaxation function with relaxation time directly proportional to dynamic viscosity. The parameters of relaxation model were obtained by the nonlinear regression analysis of thermo-mechanical experiments with different zigzag time temperature regimes. According to this method, the simultaneous obtaining of both thermal expansion coefficients is possible together with the determination of viscosity curve and of the parameters characterizing the structural relaxation process. It was found that the structural relaxation of studied glass is well described by the TNMa model and the parameters obtained can be used in modeling of the mechanical stress formation/relaxation during the glass forming/annealing.