Frequency-dependent shear modulus of glycerol near the glass transition

We have measured the frequency-dependent shear modulus of glycerol near the glass transition. The measurements, which covered three decades of frequency, probed the stress response of supercooled glycerol to small shear deformations. The shear response function has the same shape as the one obtained from ultrasonic experiments. Combined with previous measurements of ultrasound and specific heat, this result suggests that a single relaxation mechanism is responsible for such diverse phenomena as volume, shear, and enthalpy relaxations of the supercooled liquid of glycerol.