Spectroscopic and thermal studies of γ-glycine crystal grown from potassium bromide for optoelectronic applications

Single crystals of an organic nonlinear optical material γ-glycine have been synthesized by slow evaporation technique from aqueous solutions of α-glycine and potassium bromide at room temperature. Single crystal X-ray diffraction analysis confirmed the growth of γ phase of glycine. The powder X-ray diffraction of the grown crystal was recorded and indexed. Functional groups present in the sample were identified by FTIR spectral analysis. The optical absorption studies show that the UV cut-off wavelength of γ-glycine is at 238 nm and has a wide transparency window. The thermal characteristics of the grown crystal were determined by thermogravimetric and differential thermal analysis (TG/DTA), which show the thermal stability of the grown crystals. The powder second harmonic generation (SHG) efficiency of γ-glycine crystals was measured by Kurtz and Perry powder technique using Nd:YAG laser and it was found to be 2.56 times that of potassium dihydrogen phosphate (KDP) crystals.