Wang Li-Min, Richert Ranko
Department of Chemistry and Biochemistry, Arizona State University, Tempe, Arizona 85287-1604, USA.
J Phys Chem B. 2005 Jun 9;109(22):11091-4. doi: 10.1021/jp051965d.
Many hydrogen-bonded liquids, especially glass-forming cases, display a dielectric relaxation behavior that differs qualitatively from that of other simple liquids. The majority of models aimed at explaining this unusual dielectric behavior associate the prominent Debye process with structural relaxation, viscous flow, and the glass transition. We perform dielectric and calorimetric studies of glass-forming mixtures of 2-ethylhexylamine and 2-ethyl-1-hexanol across the entire composition range. The kinetic glass transition temperature derived from the large dielectric Debye peak decreases, whereas that of the much smaller and asymmetrically broadened peak increases upon addition of amine. Only the latter feature coincides with the calorimetric glass transition results, implying that molecular structure and dielectric polarization fluctuate on time scales that can differ by orders of magnitude in many hydrogen-bonding liquids.
许多氢键液体，尤其是形成玻璃的情况，表现出一种介电弛豫行为，这种行为在性质上不同于其他简单液体。大多数旨在解释这种异常介电行为的模型将突出的德拜过程与结构弛豫、粘性流动和玻璃化转变联系起来。我们对2-乙基己胺和2-乙基-1-己醇的玻璃形成混合物在整个组成范围内进行了介电和量热研究。从大的介电德拜峰得出的动力学玻璃化转变温度降低，而加入胺后，小得多且不对称展宽的峰的动力学玻璃化转变温度升高。只有后一个特征与量热玻璃化转变结果一致，这意味着在许多氢键液体中，分子结构和介电极化在时间尺度上的波动可能相差几个数量级。
