Calorimetric and polarometric study of relaxation in crystals, glasses and glassy crystals

在样品池内建立了一个电极绝热量热计。利用外加电位，可以使样品在电场中冷却。在足够低的温度下，即使电场关闭，样品也能长时间保持其极化。当这样极化的样品被加热时，它在玻璃化转变处或附近失去其极化。去极化伴随着电流的流动。通过记录去极化电流，实验确定了极化弛豫时间。同时，可以通过记录与焓弛豫有关的温度变化来测量焓弛豫时间。这两个量的同时测量使得分子重定向运动的讨论可以进行到比测量一个量更深入的层面。本方法已应用于丙醇液体玻璃和异氰酸环己烷玻璃晶态。结果是非常令人鼓舞的，因为它提供了一种实验方法，可以测量具有完全相同史前的同一样品的极化弛豫和焓弛豫，这是弛豫现象研究中非常重要的，否则难以实现的要求。用绝热量热法对富勒烯C60进行了研究，结果表明富勒烯C60为玻璃晶，玻璃化转变温度为86 K。分子重定向的活化能为21 kJ/mol/。

An adiabatic calorimeter with electrodes built in the sample cell has been constructed. By application of external potential, the sample can be cooled in an electric field. At sufficiently low temperature, the sample retains its polarization for a long time even if the electric field has been turned off. When the sample thus polarized is heated it looses its polarization at or near the glass transition. The depolarization is accompanied by flow of current. The polarization relaxation time is experimentally determined by recording the depolarization current. At the same time, the enthalpy relaxation time can be measured by the recording the temperature change associated with the relaxation. The simultaneous measurement of the two quantities allows discussion of the molecular reorientational motion to be carried out into a deeper level than is possible with measurement of one quantity. This method has been applied to a liquid glass of propyl alcohol and a glassy crystalline state of isocyanocyclohexane. The results turned out to be very encouraging because it offers a experimental method by which one can measure the polarization relaxation and enthalpy relaxation on the identical sample having exactly the same prehistory, a very important, and otherwise difficult-to-realize requirement in the study of relaxation phenomena.A fullerene C60 was investigated by adiabatic calorimetry and turned out to be a glassy crystal, with the glass transition temperature og 86 K. The activation energy of molecular reorientation is 21 kJ/mol/.