ABSTRACT
The available experimental data, including our data, show that the polymorphic transformation kinetics are quite different depending on the nature of the substance and the external conditions (temperature range of transformation, pressure). The same transformation may occur by slow thermally activated nucleation of a new phase and slow thermally activated growth of an embryo – at high temperatures, and with a very high speed, and by an athermal mechanism – at low temperatures. Between these two extremes we can find a wide range of intermediates.
