Elucidation of the Nature of Structural Relaxation in Glassy D-Sorbitol.
Elucidation of the Nature of Structural Relaxation in Glassy D-Sorbitol.
复制标题
DOI：
10.1021/acs.jpcb.9b11075
复制
发表时间：
2020-02
期刊：
影响因子：
--
通讯作者：
M. Krynski;F. Mocanu;S. Elliott
中科院分区：
文献类型：
--
作者：
M. Krynski;F. Mocanu;S. Elliott
玻璃化转变的性质和起源是凝聚态科学尚未解决的重大问题之一。随着液体在玻璃化转变温度附近冷却时粘度的迅速增加，观察到一系列动力学基序，揭示了非晶单元之间相互作用的绝对复杂性。然而，这些图案与凝固过程之间的因果关系尚不清楚。在这里，我们采用了一种新的方法来探索d-山梨醇（氢键有机玻璃的典型例子）中结构单元之间的非平凡相互作用，通过引入二面体重排指标分析来阐明松弛过程和动力学异质性，这些过程以其与玻璃稳定性的关联而闻名。我们发现α-和β-弛豫过程都是由氢键动力学的协同和非均相变化所控制的，这种变化可以用空间和二面角重排指标来描述。方法和发现是普遍适用于其他玻璃成型系统。
The nature and origin of the glass transition is one of the great unsolved problems of condensed-matter science. With the rapid increase of viscosity upon cooling the liquid near the glass-transition temperature, a range of dynamical motifs are observed, revealing the sheer complexity of interactions between the amorphous units. Yet, the causal link between those motifs and the solidification process remains unclear. Here, we apply a novel approach for exploring nontrivial interactions between structural units in d-sorbitol, a canonical example of a hydrogen-bonded organic glass, by introducing a dihedral-rearrangement indicator analysis to shed light on relaxation processes and dynamical heterogeneity, which are known for their association with stability of a glass. We find that both α- and β-relaxation processes are governed by cooperative and heterogeneous changes in hydrogen-bond dynamics that can be described by spatial and dihedral-angle rearrangement indicators. The methodology and findings are of general applicability to other glass-forming systems.