Nonlinear optical activity of anhydrous and hydrated sodium p-nitrophenolate

Differently hydrated sodium p-nitrophenolate (NPNa) crystals were obtained while growing them from different solvents such as methanol and water. Ther mal analysis and powder X-ray diffraction studies were carried out on these crystals. Kurtz powder SHG technique was used for qualitative assessment o f their nonlinear optical (NLO) activity. From the detailed single-crystal X-ray diffraction studies it is established that NPNa has three different f orms, of which only one is found to possess NLO activity. Additionally, a n ew NLO active crystal was also found to grow from aqueous solution. (C) 199 9 Elsevier Science B.V. All rights reserved.