Influence of Na2O content on the nucleation kinetics in glasses of compositions close to the Na2O•2CaO•3SiO2 stoichiometry

The kinetics of nucleation and growth of Na2O . 2CaO . 3SiO(2) crystals in glasses with small deviations from the stoichiometric composition is studied. The stationary nucleation rate, induction period, and crystal growth rate as functions of the temperature and Na2O content in the glass are measured. It is found that relatively small variations in the glass composition significantly affect the crystal nucleation rate. The experimental data are analyzed within the framework of the classical nucleation theory. It is shown that an increase in the Na2O content in the glass brings about a decrease in the kinetic and thermodynamic barriers of nucleation.