Low-frequency dielectric fluctuations near the glass transition

Abstract

The temperature and frequency dependence of thermal electricpolarization noise was investigated in glycerol at and below the glasstransition temperature. Polarization fluctuations were observed viavoltage noise which was produced within a sample capacitance cell inequilibrium. The high sensitivity and accuracy of the techniqueprovides a useful probe of dynamics in low-loss regimes of variousdielectric materials. Noise spectra exhibit a 1/fγ power lawform at lower temperatures just below the glass transition, where thenoise also exhibits unusual aging effects. The spectral exponentdecreases with temperature, extrapolating to 1.0, i.e. 1/fnoise, at a critical temperature where the noise magnitudeextrapolates to a non-zero value. The results support the possibilitythat a glassy phase transition occurs in the static limit.