Studies on the growth and characterization of benzimidazole single crystals—vertical Bridgman technique

The potential organic nonlinear optical (NLO) materials of benzimidazole single crystals have been grown by vertical Bridgman technique by optimizing the growth conditions. The crystalline perfection has been studied by high resolution X-ray diffractometry (HRXRD). Due to thermal stresses induced during growth and post-growth cooling cycle, the grown crystals were found to have some internal structural very low angle and low angle grain boundaries. After thermal treatment (annealing with slow heating and cooling rates) the observed grain boundaries were found to annulled out and the crystalline perfection has been increased up to a large extent. The laser damage threshold measurement and second-harmonic generation (SHG) studies have been made on the benzimidazole single crystal using Q-switched Nd:YAG laser as a source. 13C-NMR studies have been carried out to identify the carbon present in the grown crystal.