Crystallization of 2-propanol studied by neutron diffraction and dielectric spectroscopy in real-time

Abstract.

The crystallization of 2-propanol was investigated in order to monitor the change of the molecular dynamics with increasing crystallinity by means of real-time dielectric spectroscopy and neutron-diffraction experiments. Both experiments were performed during isothermal crystallization at 135.5 K, above the glass-transition temperature (T_g=115 K). In the dielectric spectrum was observed a moderate shift of the peak of the α-relaxation and a broadening of the spectrum. The crystallization at that temperature is explained with a simple model of the transformed volume fraction based on steady-state homogeneous nucleation of crystallites which grow at a constant rate. Although no direct information about the morphology of the sample is available, the indirect measurements by means of neutron diffraction indicate a three-dimensional crystal growth.