Spherulitic Crystal Growth Velocity in Selenium Supercooled Liquid

The spherulitic crystal growth velocity in selenium supercooled liquid has been measured by infrared microscopy in isothermal conditions for rapidly heated samples of a-Se from temperatures well below Tg. These data are compared and analyzed along with previously published data obtained on samples quenched from a temperature well above the melting point. The spherulites grew linearly over a course of time that corresponds to crystal growth controlled by crystal–liquid interface kinetics. The crystal growth velocity data obtained for these two different thermal histories can be described by the normal growth model for moderate supercoolings (ΔT 90 K) that is also consistent with morphological observations. However, the prediction based on this model still significantly deviates for intermediate supercoolings. It is shown that all experimental data in the whole temperature range (Tg < T < Tm) can be described b...