Studies on the growth, structural, thermal, mechanical and optical properties of the semiorganic nonlinear optical crystal l-glutamic acid hydrobromide

Single crystals of optically significant l-glutamic acid hydrobromide were grown from aqueous solutions and their various properties were characterized. The title compound was synthesized with stoichiometric ratio 1:1, purified by recrystallization, confirmed by powder X-ray diffraction and its solubility in double distilled water in the temperature range 30–80 °C was determined by the gravimetric method. Large dimensional (45×26×14 mm3) optically transparent single crystal of the compound was grown by a controlled slow cooling method combined with the reversible seed rotation technique. The morphological importance of the grown crystal was studied in accordance with equilibrium morphology. Samples of the grown crystal were subjected to single crystal X-ray diffraction study for structural analysis, Fourier transform infrared spectroscopy for functional group analysis, TG-DTA/DSC for thermal analysis, Vickers microhardness study for mechanical strength, UV–vis-NIR spectral analysis for optical transparency and the Kurtz powder method for SHG efficiency of the grown crystal. Results indicate that the grown crystal has significant improvement in its thermal, optical and SHG properties when compared to pure l-glutamic acid polymorphs.

► Large sized single crystals of l-glutamic acid hydrobromide were successfully grown.
► Morphological importance is reported in accordance with equilibrium morphology.
► Grown crystals have good optical transparency in the useful wavelength regions.
► Extension of UV lower cut-off and near IR upper cut-off wavelengths is reported.
► Grown crystals found improved thermal, mechanical, optical and SHG properties.