Growth and Perfection of Organic Nonlinear Optical Materials. Kinetics and Mechanism of the Growth of N-(4-Nitrophenyl)prolinol (NPP) Crystals from Methanol and Toluene Solution

Abstract

Organic nonlinear optical materials are difficult to prepare in single-crystalline form due to the inhibition of growth by the solvent. This yields poor growth characteristics which result in the development of strain and inclusions in the grown crystal. A study has been made of the growth mechanism and morphology of N-(4-nitropheny1)prolinol using both a polar and nonpolar solvent. The results are used to define conditions for the preparation of large crystals up to 2 x 0.8 x 0.8 cm3 of exceptionally high optical and structural perfection.

Dissolution Kinetics of Single Crystals of a-Lactose Monohydrate

“…Polar solids often show a high anisotropy in growth rate, which results in much lower growth rates in one polar direction than the other. [21][22][23][24] In the present case, little or no growth is observed in the (010) direction. This result implies that there is a considerable barrier to nucleation for growth to occur.…”

Preparation and Characterization of N-4-Nitrophenyl-L-prolinol Nanocrystals in Sol–Gel Matrices

“…Carbon atom numbered in Fig. 1 Chemical shift (ppm) C(1) 152.9067 C (4) 135.9528 C(3), C (5) 126.0259 C(2), C (6) 111.8605 C (8) 63.8432 C (11) 60.8317 C (9) 49.2874 C (10) 29.2105 C (7) 22.9643 …”

“…In addition, large single crystals can be grown in solution close to room temperature as in the case of N-4-nitrophenyl-L-prolinol (noted NPP in the following, see Fig. 1), for example (5). Unfortunately, the use of organic crystals for optical applications is generally limited by their insufficient chemical stability, weak thermal stability, and mechanical resistance.…”

Orientation of Organic Nanocrystals Grown in Sol–Gel Matrices under a High Magnetic Field

“…These organic phases possess other advantages such as unlimited molecular engineering and often, high laser damage thresholds. Moreover, large crystals can be grown in solutions or gels as in the case of the N-(4-nitrophenyl)-(L)-prolinol (NPP) [3,4] and 3-methyl-4-nitropyridine-1-oxide (POM) [5] and ordered polycrystalline thin films have been obtained with NPP. [6] In order to take advantage of the good NLO properties of the molecular crystals and to improve the stability of the corresponding phases, we have developed a generic process of nanocrystallization of organic phases in gel glasses.…”