Low-frequency dielectric fluctuations near the glass transition

The temperature and frequency dependence of thermal electric polarization noise was investigated in glycerol at and below the glass transition temperature. Polarization fluctuations were observed via voltage noise which was produced within a sample capacitance cell in equilibrium. The high sensitivity and accuracy of the technique provides a useful probe of dynamics in low-loss regimes of various dielectric materials. Noise spectra exhibit a $1/f^\gamma$ power law form at lower temperatures just below the glass transition, where the noise also exhibits unusual aging effects. The spectral exponent decreases with temperature, extrapolating to 1.0, i.e. 1/f noise, at a critical temperature where the noise magnitude extrapolates to a non-zero value. The results support the possibility that a glassy phase transition occurs in the static limit.