用Mach-Zehnder激光干涉仪研究PMMA的分子运动

MACH-ZEHNDER LASER INTERFEROMETER FOR THE STUDY OF MOLECULAR MOTION IN PMMA

在-60～120℃范围内,用Mach—Zehnder激光干涉仪测定了光在聚甲基丙烯酸甲酯(PMMA)样品中传播的光程随温度的变化曲线。该曲线上三个明显的突变点分别与此种高聚物的α、α_β和β弛豫的临界温度相对应。从同一曲线上还同时给出了材料的折射率和比容随温度的变化关系。

In the range -60-120℃, plots of the optical path of light transmission in PMMA vs various temperature were obtained by the Mach-Zehnder interferometer. In this curves three distinct breats were observed respectively at the critical temperatures ofa,B and aB-proce-sses in PMMA. From the same curves temperature coefficient of refractive index and thermal expansion coefficient for PMMA were estimated simultaneously.