ACTIVITY OF SUBSTRATES IN THE CATALYZED NUCLEATION OF GLASS-FORMING MELTS .1. THEORY

The nucleating activity of different insoluble additives in the heterogeneous nucleation of organic and inorganic glass-forming melts is treated from a generalized thermodynamic standpoint. The activity of a nucleating catalyst is defined through the adhesion energy and calculated from the forces of cohesion in the substrate and in the overgrowing crystal. An estimate is also made of the relative contribution of structure mismatch to the bonding energy by evaluating the total energy of misfit dislocations at the deposit/substrate interface. This approach extends and specifies the limits of application of existing concepts of crystallographic matching and mismatching. By this generalized method, there is a possibility of predicting the nucleating activity of various crystallization cores in the induced crystallization of glass-forming melts by using data on the heat of sublimation (or the temperature of melting) of the respective nucleation catalyst or the value of its thermal expansion coefficient.