Dielectric polarization noise through the glass transition

Measurements of thermal dielectric polarization noise were performed on an organic glass former. The temperature and frequency dependence of the noise was investigated in glycerol in the vicinity of its glass transition. Polarization fluctuations were observed via current or voltage noise, which were produced within a sample capacitance cell. The predictions of the fluctuation-dissipation theorem proved valid even on entering a nonequilibrium regime near the glass transition. Noise spectra exhibit power-law behavior similar to $\frac{1}{f}$ noise at lower temperatures. The measurements provide a useful spectroscopy of spontaneous structural rearrangements in dielectric and biological materials.