Molecular Crystals and Liquid Crystals Science and Technology. Section A. Molecular Crystals and Liquid Crystals, Vol.294, 263-266, 1997
Nonlinear-Optical Properties of Modified DR1/Silica Films with Highly Ordered Structures
Crosslinkable organic NLO chromophore (DRS) has been prepared and chemically incorporated into silica matrices using a sol-gel process. By monitoring the decay of UV absorbance as a function of time and temperatures, a number of electrically poled DRS/silica matrice system has been investigated to elucidate the relaxation behaviors of the oriented organic chromophore by the poling. The value of the second order NLO coefficient d(33) was 47 pm/V for the DRS/silica matrice films with 0.4 mu m thickness. In addition, from the result of dramatic decreasing of UV absorbance after poling, it is speculated that the DRS may act as a liquid crystalline mesogenic groups and effectively oriented by the poling at the phase (nematic) transition temperature (80 degrees C) and locked in by the crosslinking. The crosslinking reactions between silica matrices and DRS chromophores have been proved using Si-29 solid NMR measurement.