Crystallization kinetics in a glass-forming melt with retarded viscosity

In conventional descriptions of nucleation and crystallization kinetics, it is usually assumed that the kinetic parameters related to the viscosity of the melt depend exclusively on the current temperature of the system. On the other hand, after a rapid quench to a low temperature, T, the viscosity, η, requires a time (τ_η) to reach its equilibrium value, η_∝(T). Since the transient viscosity, η(t), can be much smaller than η_∝ and isothermal crystallization kinetics are inversely proportional to the fourth power of the viscosity, a substantial increase in the crystallized volume fraction can be anticipated compared to what is predicted using η_∝. An analytical study of this effect is presented, together with estimations of experimental observability. Typically, the latter is associated with temperatures below the glass transformation region.