THE USE OF SITE SATURATION AND ARRHENIUS ASSUMPTIONS IN THE INTERPRETATION OF NONISOTHERMAL DTA DSC CRYSTALLIZATION EXPERIMENTS

Two features associated with the interpretation of thermoanalytical crystallization experiments are investigated. First, the generality of the assumption of site saturation is examined. Since this assumption produces a major simplification of the exact expression for the volume fraction crystallized, the domain of applicability of this approximation is explored. Homogeneous crystal nucleation is examined and a broad range of crystallization parameters are considered. Next, an examination is given of a class of models which invoke an Arrhenian assumption for K(T), the crystallization rate constant, and determine crystallization activation energies from plots of ln(ln(1-X)-1) versus 1/T. Finally, a discussion is presented of the physical interpretation of the activation energies.