Nucleation and crystal growth in water containing soda-lime-silica glasses

The nucleation and crystal growth in glasses of composition close, to Na2O . 2CaO . 3SiO(2) were investigated. The steady state nucleation rate, the time lag of nucleation and also the crystal growth rate were measured as a function of the temperature for three glasses with different water content, introduced by bubbling steam through the liquids. It was shown that an increase in the water content results in the following: a decrease of the time lag of nucleation, a shift of the temperature for the maximum nucleation rate to lower temperatures, accompanied by an increase of nucleation rate values, and an increase of crystal growth rate. The analysis of the nucleation rate was performed in the framework of the classical theory of nucleation in condensed systems. In doing it the time lag of nucleation was used to estimate the kinetic barrier to nucleation. We conclude that at temperatures higher than the glass transition temperature the water content does not affect the thermodynamic barrier of nucleation but results in a decrease of the kinetic barrier. (C) 1999 Published by Elsevier Science B.V. All rights reserved.