DEVELOPMENT OF AN OPTICAL LIQUID HIGH-PRESSURE-CELL AND ITS APPLICATION TO VISUAL OBSERVATION OF PRESSURE-DRIVEN CRYSTAL-GROWTH

An optical liquid high pressure cell generating pressures up to 1 GPa was developed for visual observation of crystal growth, which can sett le a supersaturation very rapidly by a pressure operation. By using a soft transparent sample bag, the cell provides high reliability of pre ssure control (less than+/-1 MPa) and easy handling. The method of con structing a phase diagram was developed for deducing the supersaturati on. The pressure and supersaturation dependences of the nucleation and the growth form of p-xylene crystals were observed, which can be expl ained by the pressure and concentration dependence of the surface and the edge free energy, respectively.