Physikalisches Institut, Universität Bayreuth, Bayreuth 95440, Germany.
J Chem Phys. 2009 Nov 14;131(18):184510. doi: 10.1063/1.3258430.
Dielectric loss spectra of glass forming liquids are analyzed, with emphasis on systems for which a peak due to a secondary relaxation is not immediately obvious. Thus, glass formers are considered for which the high-frequency flank of the alpha-relaxation peak appears to be dominated by a so-called wing contribution. It is shown that even for such supercooled liquids the shape of the alpha-peak has to be characterized by two parameters. By performing a series of aging experiments it is demonstrated that the high-frequency flank of the alpha-relaxation, assumed to follow a power-law behavior, is superimposed by contributions from an excess wing and from a beta-relaxation peak. In particular, the excess wing, previously associated with either the alpha- or the beta-relaxation, is identified as a feature that evolves in its own right. It is argued that excess wing and beta-relaxation are always present albeit with relative strengths that may vastly differ from glass former to glass former.
对玻璃形成液体的介电损耗谱进行了分析，重点研究了那些没有明显的次级松弛峰的体系。因此，我们考虑了那些高频侧α弛豫峰似乎主要由所谓的翼贡献主导的玻璃形成体。结果表明，即使对于这种过冷液体，α峰的形状也必须用两个参数来描述。通过进行一系列的老化实验，证明了假设遵循幂律行为的α弛豫的高频侧被过剩翼和β弛豫峰的贡献所叠加。特别是，以前与α或β弛豫相关的过剩翼被确定为一个独立演变的特征。有人认为，过剩翼和β弛豫总是存在的，尽管它们的相对强度可能因玻璃形成体而异。
