根据热膨胀原理,利用基于衰减全反射原理建立的CCD薄膜实时监控系统,提出了测量聚合物材料的玻璃化转变温度(Tg)的方法。用监测系统实时监测聚合物薄膜在升温过程中薄膜折射率及厚度的变化。实验结果发现薄膜的热膨胀系数β和温度相关的折射率dn/dT在升温过程中发生了突变,这个突变点所对应的温度就是聚合物薄膜的Tg。以掺杂型聚合物DR1/PMMA薄膜为例,给出了测量过程和实验结果,并检验了用该方法测量聚合物薄膜Tg的重复性和可靠性。

According to thermal expansion principle,a novel real-time method is proposed in this paper for determining the glass transition temperature (Tg) of thin polymer films based on the attenuated total reflection technique. The method is that the changing values of the refractive index and the thickness of the polymer film can be determined with the ascending temperature using the real-time system. Experimental results definitely show that curves of temperature dependence of the thermal expansion coefficient (β) and the refractive index (dn/dT) change discontinuously and exist a same intersection point. The temperature of intersection point is the polymericTg. With host-guest DR1/PMMA,the measurement procedures and experimental results are given. The repeatability and reliability of measuring Tg of polymer by this method are examined.