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

本研究首次提出了利用激光激发温度波测量动态热容频率依赖性的新方法。其次，将该方法应用于脆性液体玻璃化转变的慢弛豫过程的研究。为了确定动态热容的频率依赖性，我们设计了如下实验装置。利用经特殊电路精确调制强度的稳频半导体激光器在样品表面精确激发温度波。将样品室插入真空容器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脆性液体的玻璃化转变。的弛豫频率和弛豫时间的分布的温度依赖性被准确地确定为温度的函数。测量介电色散用于比较。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-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.