Glass transition of constrained system measured by position sensitive dynamics measurements

用差示扫描量热法和介电弛豫谱研究了聚苯乙烯和聚2-氯苯乙烯叠层薄膜的玻璃化转变动力学。在等温退火过程中，聚2-氯苯乙烯叠层薄膜的α-过程动力学表现出从单薄膜状动力学到块体状动力学的时间演化。随着退火时间的增加，α过程的弛豫速率变小。退火过程中α动力学演化的时间尺度比爬行动力学演化的时间尺度要长。同时，随着退火时间的增加，α过程弛豫时间的温度依赖性从类Arrhenius关系变为Vogel-Fulcher-Tammann关系。随着等温退火时间的增加，脆性指数增加，α弛豫时间分布变小。在α过程中观察到的变化进行了讨论相对于堆叠的薄聚合物膜的薄层之间的界面相互作用。

The glass transition dynamics of stacked thin films of polystyrene and poly(2-chlorostyrene) were investigated using differential scanning calorimetry and dielectric relaxation spectroscopy. The α-process dynamics of stacked thin films of poly(2-chlorostyrene) show a time evolution from single-thin-film-like dynamics to bulk-like dynamics during the isothermal annealing process. The relaxation rate of the α process becomes smaller with increase in the annealing time. The time scale for the evolution of the α dynamics during the annealing process is very long compared with that for the reptation dynamics. At the same time, the temperature dependence of the relaxation time for the α process changes from Arrhenius-like to Vogel-Fulcher-Tammann dependence with increase of the annealing time. The fragility index increases and the distribution of the α-relaxation times becomes smaller with increase in the annealing time for isothermal annealing. The observed change in the α process is discussed with respect to the interfacial interaction between the thin layers of stacked thin polymer films.