Spectral selectivity in the slow β-relaxation of a molecular glass

The time-resolved electric-field relaxation in glassy D-sorbitol is measured by dielectric hole-burning, i.e. with and without a preceding high electric sinusoidal burn field. The question is whether the burn-induced modifications of the response are frequency-selective (dielectric "holes") and thus indicative of heterogeneous dynamics, where slow and fast responses coexist in the material. For burn fields between 250 and 440 kV/cm such holes in the responses are observed, whose positions shift linearly with the inverse burn frequency. Recovery time measurements indicate that these modifications of the Johari-Goldstein process in glassy D-sorbitol are long lived.