T-M DSC analysis of kinetics in phase transitions having broad distribution of transition temperatures

摘要

Temperature-Modulated DSC analysis methods are discussed for the kinetics in the 1st-order phase transitions having intrinsically broad distribution of transition temperatures: polymeric systems, water confined in nano pores, and solid-solid transformation in an alloy. Based on a modeling of the lst-order kinetic equation with a rate coefficient dependent on the degree of supercooling or superheating, we have analyzed the kinetic response to temperature modulation appearing as the frequency dispersion of an effective dynamic heat capacity with a characteristic time dependent on the underlying constant scan rate. From the analysis, we can obtain valuable information on the nature of the transition kinetics in terms of the rate determining step, i.e. the dependence of transition rate on the supercooling or superheating.