Identifying the structural relaxation dynamics in a strongly asymmetric binary glass former.
Identifying the structural relaxation dynamics in a strongly asymmetric binary glass former.
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DOI：
10.1063/5.0046361
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发表时间：
2021-04
期刊：
影响因子：
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通讯作者：
Xiao Jin;Zijing Li;Yingdan Liu;S. Feng;Li-Min Wang
中科院分区：
文献类型：
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作者：
Xiao Jin;Zijing Li;Yingdan Liu;S. Feng;Li-Min Wang
在这里，我们提供了量热和介电的研究，在不对称的二元混合物构成的2-甲基吡啶和三苯乙烯。在混合物中观察到量热玻璃化转变的极端加宽，这伴随着由两种技术定义的玻璃化转变温度的大失配。由于在中间浓度的混合物中确定了弛豫分散体的大加宽，检测到弛豫分散体的强温度依赖性。从Tool-Narayanaswamy-Moynihan-Hodge模型导出的拉伸指数和非线性因子之间的关系显示出与由纯分子玻璃形成者和对称混合物建立的关系的显著变化。这些异常的行为表明，一个极端的动力学解耦模式所施加的发生强烈的浓度波动。
Here, we provide calorimetric and dielectric studies in asymmetric binary mixtures constituted by 2-picoline and triphenylethylene. Extreme broadening of the calorimetric glass transition is observed in the mixtures, which is accompanied by a large mismatch of the glass transition temperatures defined by the two techniques. As large broadening in the relaxation dispersion is identified in the mixtures of intermediate concentrations, strong temperature dependence of the relaxation dispersion is detected. The relation between the stretching exponent and non-linear factor derived from the Tool-Narayanaswamy-Moynihan-Hodge model shows a remarkable shift from the one established by pure molecular glass formers and symmetric mixtures. The unusual behaviors suggest an extreme dynamical decoupling mode imposed by the occurrence of strong concentration fluctuation.