Lunkenheimer Peter, Humann Felix, Loidl Alois, Samwer Konrad
Experimental Physics V, Center for Electronic Correlations and Magnetism, University of Augsburg, 86159 Augsburg, Germany.
I. Physikalisches Institut, Universität Göttingen, 37077 Göttingen, Germany.
J Chem Phys. 2020 Sep 28;153(12):124507. doi: 10.1063/5.0014457.
A recently published analytical model describing and predicting elasticity, viscosity, and fragility of metallic melts is applied for the analysis of about 30 nonmetallic glassy systems, ranging from oxide network glasses to alcohols, low-molecular-weight liquids, polymers, plastic crystals, and even ionic glass formers. The model is based on the power-law exponent λ representing the steepness parameter of the repulsive part of the inter-atomic or inter-molecular potential and the thermal-expansion parameter α determined by the attractive anharmonic part of the effective interaction. It allows fitting the typical super-Arrhenius temperature variation of the viscosity or dielectric relaxation time for various classes of glass-forming matter, over many decades. We discuss the relation of the model parameters found for all these different glass-forming systems to the fragility parameter m and detect a correlation of λ and m for the non-metallic glass formers, in accord with the model predictions. Within the framework of this model, the fragility of glass formers can be traced back to microscopic model parameters characterizing the intermolecular interactions.
最近发表的一个描述和预测金属熔体弹性、粘度和脆性的分析模型，被用于分析约30种非金属玻璃态体系，范围从氧化物网络玻璃到醇类、低分子量液体、聚合物、塑性晶体，甚至离子玻璃形成体。该模型基于幂律指数λ（代表原子间或分子间势的排斥部分的陡度参数）和由有效相互作用的吸引非谐部分确定的热膨胀参数α。它能够在几十年的时间跨度内，拟合各类玻璃形成物质的粘度或介电弛豫时间典型的超阿仑尼乌斯温度变化。我们讨论了在所有这些不同玻璃形成体系中找到的模型参数与脆性参数m的关系，并发现对于非金属玻璃形成体，λ和m存在相关性，这与模型预测一致。在该模型的框架内，玻璃形成体的脆性可以追溯到表征分子间相互作用的微观模型参数。
