Fast Dynamics of Glass-Forming Glycerol Studied by Dielectric Spectroscopy

Dielectric spectroscopy up to 370 GHz has been performed on supercooled glycerol for temperatures between 250 and 330 K. The high-frequency dielectric loss, ${\ensuremath{\varepsilon}}^{\ensuremath{'}\ensuremath{'}}$, has been investigated by coherent-source submillimeter-wave spectroscopy. Special attention is given to the dielectric loss in the crossover regime from the structural relaxation to the far-infrared response. A minimum is observed in ${\ensuremath{\varepsilon}}^{\ensuremath{'}\ensuremath{'}}(\ensuremath{\nu})$ which is compared to theoretical concepts that predict fast relaxational processes.