分子非晶体系中结构弛豫的非线性动力学研究

Nonlinear dynamics of structural relaxation in molecular amorphous systems

为了深入认识非晶体系中的非线性动力学,并了解非线性参数与其他动力学特征参量之间的关联,本文针对小分子非晶体系对非线性弛豫动力学进行了研究,利用Tool-Narayanaswamy-Moynihan-Hodge(TNMH)方程获得非线性因子。在纯物质中发现非线性因子与非指数因子之间关联显著,具有同步变化趋势,且前者普遍低于后者。二元混合体系中也发现同样的规律。应用TNMH等温方程也同样解释了等温退火动力学行为,证明了TNMH方程的广泛适用性。最后对非线性弛豫所面临的部分问题进行了简要总结。

To gain in-depth understanding of the nonlinear dynamics in the amorphous systems,in particular its correlation with other dynamic characteristic parameters,the nonlinear relaxation dynamics for the small molecule amorphous systems is studied in this paper by using Tool-Narayanaswamy-Moynihan-Hodge equation,and the nonlinear factors are determined.For pure substances,we found that the nonlinear factors are positively correlated with the non-exponential factors,but the former is generally slightly lower than the latter.The same law is also found in binary mixtures of various mixing modes manifested by positive and negative enthalpies of mixing.The application of the isothermal TNMH equation well explain the isothermal annealing behavior.Finally,some challenges for the nonlinear relaxation studies are briefly summarized.