3.1.2. Kinetics of phase transition
The kinetics of the liquid-to-solid phase transition was investigated during sound speed measurements, see Fig. 3. Pressure changes, occurring during liquid-to-solid phase transition, were registered with the piston locked in a fixed position. At first (starting at the point b at a given temperature) the pressure remained constant. Subsequently, a sudden decrease of pressure was observed (at point b1), due to a liquid-to-solid phase transition in olive oil. The moment of time in which, pressure drops spontaneously with further increase in the speed of sound is the signature of the beginning of the phase transition. Finally, the pressure level stabilized (point c). This means that the liquid-to-solid phase transition was completed. As a result, a new high-pressure solidlike phase in olive oil has emerged. Changes in temperature influence considerably the time course (evolution) of phase transition. One can see in Fig. 3, that with the increase of temperature liquidto- solid phase transition started at a higher value of pressure and the induction time (from point b to point b1) is larger.