抄録
X-ray diffraction studies on the phase transition behavior of crystalline polymorphs of 7OCB and 8OCB has been carried out by using synchrotron radiation at SPring-8. In 7OCB, it was confirmed that the square-plate crystal transformed to the needle crystal at 40 ℃ and the pattern of a new phase appeared at 50 ℃, which changed to the pattern of the most stable phase at 52 ℃. In 8OCB, the peaks of d = 3.58 and 1.81 Å decreased at 41 ℃, while other peaks increased. Then, the pattern becomes only the most stable phase at 49 ℃. We are now examining the cause of the drastic change at 41 ℃.
