Doumenc F, Bodiguel H, Guerrier B
Université Pierre et Marie Curie-Paris 6, Université Paris-Sud, CNRS, Laboratoire FAST, F-91405, France.
Eur Phys J E Soft Matter. 2008 Sep;27(1):3-11. doi: 10.1140/epje/i2008-10345-0.
Gravimetry experiments in a well-controlled environment have been performed to investigate aging for a glassy PMMA/toluene film. The temperature is constant and the control parameter is the solvent vapor pressure above the film (i.e. the activity). Several experimental protocols have been used, starting from a high activity where the film is swollen and rubbery and then aging the film at different activities below the glass transition. Desorption and resorption curves have been compared for the different protocols, in particular in terms of the softening time, i.e. the time needed by the sample to recover an equilibrium state at high activity. Non-trivial behaviors have been observed, especially at small activities (deep quench). A model is proposed, extending the Leibler-Sekimoto approach to take into account the structural relaxation in the glassy state, using the Tool formalism. This model well captures some of the observed phenomena, but fails in describing the specific kinetics observed when aging is followed by a short but deep quench.
已在可控环境中进行重量分析实验，以研究玻璃态聚甲基丙烯酸甲酯/甲苯薄膜的老化过程。温度保持恒定，控制参数为薄膜上方的溶剂蒸气压（即活度）。采用了几种实验方案，从高活度开始，此时薄膜膨胀且呈橡胶态，然后在低于玻璃化转变温度的不同活度下使薄膜老化。已对不同方案的解吸和再吸附曲线进行了比较，特别是在软化时间方面，即样品在高活度下恢复平衡状态所需的时间。观察到了一些非平凡行为，尤其是在低活度（深度淬火）时。提出了一个模型，扩展了莱布勒 - 关本方法，使用图尔形式主义来考虑玻璃态下的结构弛豫。该模型很好地捕捉了一些观察到的现象，但在描述老化后紧接着进行短时间但深度淬火时观察到的特定动力学方面却无能为力。
