Non-linear optical monitoring of melting processes in (TEA)–CoCl2Br2 ferroelectric nanocrystallites incorporated into polymer matrices

Photoinduced optical second harmonic generation (PISHG) and differential scanning calorimetry (DSC) methods were used for study of tetraethyl-ammonium (TEA)–CoCl2Br2 ferroelectric nanocrystallites (about 50 nm) near melting point. It was shown that PISHG is more sensitive to melting temperature compared to the DSC. This is caused by sensitivity of PISHG due to contribution both of ground electron states as well as of excited ones contrary to the DSC method where principal role is played by ground states.