NONRESONANT SPECTRAL HOLE-BURNING IN THE SLOW DIELECTRIC RESPONSE OF SUPERCOOLED LIQUIDS

Large-amplitude, low-frequency electric fields can be used to burn spe ctral holes in the dielectric response of supercooled propylene carbon ate and glycerol. This ability to selectively modify the dielectric re sponse establishes that the non-Debye behavior results from a distribu tion of relaxation times, Refilling of the spectral hole was consisten t with a single recovery time that coincided with the peak in the dist ribution. Moreover, refilling occurred without significant broadening, which indicates negligible direct exchange between the degrees of fre edom that responded to the field. Nonresonant spectral hole burning fa cilitates direct investigation of the intrinsic response of systems th at exhibit nonexponential relaxation.