Effect of KCl addition on crystal growth and spectral properties of glycine single crystals

Glycine usually crystallizes as the metastable α-polymorph from pure aqueous solution. The polymorph, γ-form of glycine can be crystallized only in presence of additive. In the present work, γ-glycine has been crystallized by using potassium chloride (KCl) as additive at ambient temperature by solvent evaporation method. The form of crystallization is confirmed by X-ray powder diffraction method. Spectroscopic and thermal studies have been carried out for analyzing the presence of functional groups, thermal stability and decomposition of the sample. The results indicate that the KCl is doped into the γ-glycine. The optical transparency of the γ-glycine in the ultraviolet–visible region has been studied by recording the optical transmission spectrum. Second harmonic generation (SHG) conversion efficiency has been estimated as 120 mV and the output power by the crystal is less than that of potassium dihydrogen phosphate crystal.