Cluster kinetics for glassforming materials Original Research Article

We propose that cluster kinetics based on monomer–cluster, addition–dissociation and cluster fission–fusion provide a way to understand glassforming behavior. The four rate coefficients for the transformations are Arrhenius functions of temperature. Local equilibrium relations for the reversible rates provide expressions for monomer and amorphous cluster concentrations that are related to the Kauzmann temperature and supercooled liquid viscosity. Cluster dynamics are related to observable vitrification kinetics through free volume theory. With a single fitting parameter representing phase transformation energies, the double exponential (nonArrhenius) temperature dependence for viscosity and dielectric relaxation time compares well with experimental data. The one energy parameter alone provides an interpretation for strong and fragile glass materials.