Nakanishi Masahiro, Nozaki Ryusuke
Department of Physics, Faculty of Science, Hokkaido University, Sapporo, Hokkaido, Japan.
Phys Rev E Stat Nonlin Soft Matter Phys. 2011 May;83(5 Pt 1):051503. doi: 10.1103/PhysRevE.83.051503. Epub 2011 May 13.
We have investigated the glass transitions of trihydric alcohols using broadband dielectric spectroscopy, and compare the results with those previously reported for sugar alcohols. Although a systematic glass transition feature related to molecular size has been reported for sugar alcohols, the essential factor governing this feature is still unclear because the number of carbon atoms (N(C)) and the number of OH groups (N(OH)) per molecule are identical in sugar alcohols. By examining trihydric alcohols (N(C)≠N(OH)), we conclude that N(OH) is dominant for the characteristics of the slow dynamics, such as fragility and glass transition temperature. This result suggests that the topological structure of the hydrogen-bonding network (coordination number) plays an important role in the glass transition of polyhydric alcohols. Furthermore, the orientational correlation factor evaluated using the Kirkwood-Fröhlich theory reveals a similarity in hydrogen bond formation among a variety of polyhydric alcohols. Based on these two experimental results, we discuss a possible physical picture of the glass transition of polyhydric alcohols.
我们使用宽带介电谱研究了三元醇的玻璃化转变，并将结果与先前报道的糖醇的结果进行了比较。尽管已报道糖醇存在与分子大小相关的系统玻璃化转变特征，但由于糖醇中每个分子的碳原子数（N(C)）和羟基数量（N(OH)）相同，控制该特征的关键因素仍不明确。通过研究三元醇（N(C)≠N(OH)），我们得出结论，对于诸如脆性和玻璃化转变温度等慢动力学特征，N(OH)起主导作用。这一结果表明，氢键网络的拓扑结构（配位数）在多元醇的玻璃化转变中起重要作用。此外，使用柯克伍德 - 弗勒利希理论评估的取向相关因子揭示了多种多元醇之间氢键形成的相似性。基于这两个实验结果，我们讨论了多元醇玻璃化转变可能的物理图像。
