Dielectric hole burning: Signature of dielectric and thermal relaxation time heterogeneity

We have calculated the effects of dielectric hole burning on the basis of the frequency dependent dielectric relaxation epsilon(omega) and specific heat c(p)(omega) of glycerol and assuming heterogeneous dynamics where the dielectric and thermal relaxation times are correlated quantities. The heat generated in the sample is determined from the time dependent electric field and polarization, i.e., without involving steady-state approximations. The calculations mimic the protocol of recent hole-burning experiments on glycerol [K. Duvvuri and R. Richert, J. Chem. Phys. 118, 1356 (2003)], including the high-field burn-process, the phase-cycle employed to eliminate the linear response to the high field, the detection in terms of the electric modulus M(t), and the signal normalization. Without using any fit parameters, this model is capable of quantitatively reproducing the amplitudes, shapes, and peak positions of observed dielectric holes, together with their dependence on the burn frequency and the waiting time between the pump and probe processes. Therefore, frequency selective local heating of the modes of motion associated with the structural relaxation resulting from the dielectric loss fully accounts for the dielectric hole burning effects. (C) 2003 American Institute of Physics.