Crystal Nucleation in Soda–Lime–Silica Glass at Temperatures below the Glass Transition Temperature

The effect of crystal nuclei formed during the production of glass on the kinetics of nucleation of crystals in it at temperatures below the glass transition temperature is studied. A glass composition of 22.4Na2O ⋅ 28.0CaO ⋅ 49.6SiO2 (mol %) is studied (glass transition temperature 540°C). Using the development method, the dependence of the number of nucleated crystals on the heat treatment time is determined at a temperature of 500°C. The nuclei of crystals formed during the production of glass lead to an unusual, in the form of a step, initial section of the curve N(t). The rate of stationary nucleation of crystals with a long time of nucleation heat treatment exceeding the induction period of crystal nucleation is determined. The reasons for the unusual initial nature of the dependence N(t) are discussed. The data obtained make it possible to expand the temperature dependences of the stationary rate and the induction period of crystal nucleation for the given glass toward low temperatures.