一种异质低冷液体和玻璃模型,考虑温度依赖的非指数性和度波动
1Department of Materials Science and Engineering, University of Arizona, Tucson, Arizona 85712, USA.
The Journal of chemical physics
|May 15, 2024
概括
一个新的模型通过考虑虚拟温度的分布来捕捉玻璃和液体的动态异质性. 这种方法准确地预测了温度依赖的非指数行为和值波动,改进了现有的模型.
科学领域:
- 材料科学 材料科学 材料科学
- 物理化学 物理化学
- 凝聚物质物理学 凝聚物质物理学
背景情况:
- 动态异质性是玻璃和低冷液体的关键特征,影响系统动态,如非指数性和度波动.
- 现有的模型,如工具-纳拉亚纳斯瓦米-莫伊尼汉 (TNM),往往无法完全捕捉这种异质动态的复杂性.
研究的目的:
- 提出一种新型模型,准确预测玻璃形成液体和玻璃的温度依赖的非指数行为.
- 扩展TNM框架,将平衡虚拟温度 (Tfe) 的分布纳入,以考虑液体和玻璃的异质性.
主要方法:
- 开发了一个模型,将TNM框架扩展到Tfe的分布,以表示低冷液体和玻璃中的异质性.
- 采用标准差分扫描热度计 (DSC) 曲线进行模拟.
- 使用Kohlrauch-Williams-Watts (KWW) 方程计算非指数性参数 (βKWW),并将其与实验数据进行比较.
主要成果:
- 该模型成功地预测了各种有机和无机液体和玻璃的温度依赖非指数性 (βKWW),与实验结果有很好的一致性.
- 该模型准确地描述了远离平衡的放松动态,在酸盐系统中,TNM模型失败了.
- 在同热回火过程中模拟的虚拟温度波动 (δTf) 与报告的度波动具有定性一致性,突出显示了冷却速率的依赖性.
结论:
- 拟议的模型包含了Tfe的分布,有效地捕捉了玻璃成型系统中的动态异质性和温度依赖的非指数性.
- 与TNM等传统模型相比,这种方法提供了更全面的放松动态描述,特别是在非平衡条件下.
- 这项研究强调了冷却速率在异热化过程中度波动的演变中的关键作用.
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