Measurement of non-equilibrium dynamical heat capacity by utilizin laser excited temperature wave

在本研究中，首次提出了利用激光激发的温度波测量动态热容随频率变化的新方法。其次，利用该方法研究了易碎液体玻璃-液体转变过程中的慢弛豫过程。为了确定动态热容与频率的关系，对实验装置进行了精心设计。利用稳定的半导体激光器精确地激发样品表面的温度波，并通过特殊的电路精确地调制其强度。样品室被插入真空室中，以避免声学噪声和振动。利用上述实验装置，研究了甘油、丙二醇和丙醇这三种典型的易碎液体的玻璃化转变。精确地确定了弛豫频率的温度依赖关系和弛豫时间的分布。为了比较，测量了介电色散。此外，还测量了拉曼散射，以明确原子的运动。根据这些结果，讨论了液体-玻璃转变的动力学性质。

In this research the new method to measure the frequency dependence of dynamical heat capacity has been developed by utilizing the laser excited temperature waves at first. Secondly this method has been applied to investigate slow relaxation process in the liquid-glass transition of fragile liquids.In order to determine the frequency dependence of dynamical heat capacity the experimental setup was carefully designed as follows. The temperature waves were accurately excited on the surface of a sample by the stabilized semiconductor laser of which intensity was accurately modulated by the special electric circuit. The sample chamber was inserted in a vacuum vessel to avoid an acoustic noise and vibration. The liquid glass transitions of glycerol propylene glycol and propanol, which are typical materials of fragile liquid, were studied by the use of the experimental setup described above. The temperature dependences of the relaxation frequency and the distribution of relaxation time were accurately determined as a function of temperature. The dielectric dispersion was measured for the comparison. Furthermore Raman scattering was also measured to make clear the atomic motion. From these results the dynamical properties of liquid-glass transition was discussed.