Kinetics of crystalline-noncrystalline phase transition of sucrose crystal

Microphase.Co.,Ltd* Institute of Materials Science, University of Tsukuba, Japan** *National Institute of Advanced Industrial Science and Technology, Tsukuba 305-8565, Japan***
○Taro Fujita* Takahashi Kunimitsu** Takahashi Takahashi*** Ken-ichi Ohshima**

Sugar, whose principal ingredient is the sucrose, is one of functional materials for developing the battery of emvironmental intention by using the relation among the enzyme, the micro-organism, and the photocatalyst technology. However, melting points among sucrose crystals with high purity are occasionally different from each other and the melting points quoted from references range 433K to 464K. It has been assumed that a little impurity and moisture content in the sample caused different melting points in addition to the method how to grow the specimen. There are few X-ray structural reports on microscopic phenomena of the melting, though macroscopic observations of the melting point were performed with the use of differential scanning calorimetry and optical microscope. We have measured in-situ X-ray diffraction intensities for the sucrose until the melting point. When temperature was kept constant, the intensity decreased rapidly after retarding time, which is corresponding to starting the melting (tm.) The relation between tm. and the holding temperature is not monotonous decrease with increasing the temperature, but has the minimum around 160℃. Present study gives an important information of understanding the melting point described above.