Glass-forming ability versus stability of silicate glasses. II. Theoretical demonstration

Possible relationships between measures of glass stability (GS) against devitrification on heating (evaluated by the Hruby parameter K-H = (T-c(h) - T-g)/(T-m - T-c(h)), and the parameter K-w = (T-c(h) - T-g)/T-m) and a criterion of glass-forming ability (GFA) - the critical cooling rate - were investigated by computing non-isothermal crystallization for typical values of the main quantities that control crystal nucleation and growth in silicate glasses. We limit these quantities to one thermodynamic parameter - the melting entropy (DeltaS(m)) and two kinetic parameters that control the viscosity (B and T-0 in the Vogel-Fulcher-Tamman equation or T-g and alpha in Avramov's equation). The effect of heterogeneous nucleation and, in particular, the possible role of the surface as active substrate is tested. The results presented herein demonstrate that GS and GFA are indeed related concepts. (C) 2003 Elsevier Science B.V. All rights reserved.