We have measured the frequency-dependent specific heat of glycerol and propylene glycol near the glass transition. The measurements, covering a frequency range of five decades, probe the linear response of these supercooled liquids to small perturbations from equilibrium. The specific heat of these two liquids contains a contribution which relaxes increasingly slowly as the temperature is lowered. The relaxation time measured by specific-heat spectroscopy has the same temperature dependence as that measured by other techniques. This suggests that a single mechanism is responsible for all of the observed phenomena associated with the glass transition in these materials.

• Received 10 February 1986

DOI:https://doi.org/10.1103/PhysRevB.34.1631