COMMENTS ON THE ALPHA-PEAK SHAPES FOR RELAXATION IN SUPERCOOLED LIQUIDS

The alpha-peak master functions as obtained within the mode coupling theory for the supercooled liquid dynamics near the glass transition singularity are discussed. Double peak phenomena are found as a generic feature of the theory related to the self crossing of the transition hypersurface. They lead to two scenarios for liquid to glass transitions characterized by alpha'-alpha-peak pairs and by alpha-resonances accompanied by gamma-peaks. An efficient numerical procedure is developed for the solution of the non-linear scaling equations for the master functions. A schematic three component model is used to fit quantitatively the dielectric loss spectra of polyvinylacetate, ortho-terphenyl, CaKNO3 and poly propylene glycol, which all deviate strongly from the Kohlrausch decay pattern. The model yields also triple resonances of alpha-gamma-delta-peaks.