The temperature evolution of the broadband 10−6-1010 Hz dielectric susceptibility of the paradigmatic glass formers glycerol, propylene carbonate, and fluoro-aniline is analyzed assuming a three-step relaxation due to the α-process, its excess wing, and a β-process. We find that the α-peak and the wing can be described by susceptibility functions with temperature-independent high-frequency exponents, while the relative weight of these contributions does depend on the temperature. The excess wing and the β-process are distinct phenomena; in particular, the relaxation strength of the excess wing grows with decreasing the temperature, contrary to that of the β-process. In our interpretation, the frequency-temperature superposition of the α-process is valid for all temperatures; in the case of glycerol, a typical β-process is unambiguously identified for the first time.
@article{arxiv.cond-mat/0604597,
title = {Does frequency-temperature superposition hold in deeply super-cooled liquids?},
author = {Catalin Gainaru and Alexander Brodin and Vladimir Novikov and Ernst A. Rössler},
journal= {arXiv preprint arXiv:cond-mat/0604597},
year = {2007}
}