Heat Capacity and Entropy at the Glass Transition

Frequency resolved non-linear dielectric relaxation experiments at high electric fields are used to conduct a 'reversed' heat capacity experiment, where the energy is absorbed by the configurational modes and only eventually transferred as heat to the phonon bath. The understanding of the nanoscopic energy-flow is quantitative and allows us to extract the configurational contribution to heat capacity and entropy near the glass transition of these supercooled liquids. It is found that the excess heat capacity is largely configurational only for liquids that are not fragile in terms of the strong-fragile pattern.