HEAT-CAPACITY SPECTROSCOPY COMPARED TO OTHER LINEAR-RESPONSE METHODS AT THE DYNAMIC GLASS-TRANSITION IN POLY(VINYL ACETATE)

Heat capacity spectroscopy measurements in the frequency range from 1. 25 to 12 600 rad/s at the dynamic glass transition in poly(vinyl aceta te) are reported. The data are compared to results of dielectric and s hear spectroscopy in a comparable frequency range on the same sample. The peaks of the different imaginary parts do not have the same positi on across the main transition zone. The sequence of the peaks with inc reasing frequency is as follows: dielectric compliance, entropy compli ance, and shear modulus. The distances between the different peaks are 0.3 +/- 0.4 and 1.0 +/- 0.4 frequency decades, respectively.