Effect of pure and mixed solvents on the solubility, crystal growth and morphology of ethyl p-dimethylamino benzoate (EDMAB): An organic nonlinear optical material

The effects of pure and mixed solvents of ethanol and acetone on solubility, nucleation and growth of ethyl p-dimethylamino benzoate (EDMAB) were investigated. It was found that solubility of EDMAB increased as the volume ratio of acetone increased in the mixed solvent. Growth experiments were performed at 32 °C using pure and mixed solvents with different volume ratios of ethanol and acetone. Bulk single crystals of EDMAB were grown-in the experiment conducted using mixed solvent of 25% acetone and 75% of ethanol, whereas thin platelet crystal of EDMAB was obtained in the experiment conducted using pure ethanol. The acetone rich system resulted in uncontrolled nucleation with large number of tiny crystals, possibly due to high vapor pressure of acetone. The grown crystals were subjected to various analytical studies such as powder X-ray diffraction, Vickers microhardness, dielectric studies as a function of frequency and optical transmission and the powder Kurtz method.