Calorimetric Studies of the Crystallization Process of N-Nitrophenyl-L

A. LEYDERMAN; S.-X. QU; N. ORTEGA; C.A. CONDAT

Crystal Materials for Nonlinear Optical Devices and Microgravity Science - Proc. of the SPIE

SPIE - The International Society for Optical Engineering

Año: 2002; p. 43 - 50

The crystallization of the N-4-nitrophenyl-L-prolinol (NPP) organic glass was investigated by differential scanning calorimetry (DSC). The results showed the influence of temperature and temporal treatment of the melt on the crystallization process obtained while cooling from the liquid or during heating from the glass state. The behavior of the crystallization kinetics from the glass state was studied under both isothermal and nonisothermal conditions. In the first case, DSC thermograms were recording at heating rates from 2 to 40 oC/min. The crystallization temperature was found to depend on heating rates. Two crystallization phases have been found during the heating of the sample from the glass-like disordered states in the continuing cycling of DSC. In the second case, isothermal crystallization was observed at temperatures ranging between the glass transition and crystallization points.