Preparation and nonlinear optical properties of hybrid sol–gel films doped with triphenylamino-substituted chromophores

Two similar triphenylamino-substituted chromophores with and without hydroxyl end, named TIOH and TI, respectively, were synthesized and incorporated into hybrid organic–inorganic materials derived from 3-glydoxypropyltrimethoxysilane (GPTMS), tetraethoxysilane (TEOS) and 3-aminopropyltriethoxysilane (APTES). These stilbene-type chromophores were characterized by elemental analysis, 1H NMR, FTIR, UV–vis spectra and thermogravimetric analysis (TGA). The hyperpolarizabilities were characterized through solvatochromic method. Both chromophores possess higher thermal stability and competitive hyperpolarizabilities compared with commercially available nonlinear optical dyes such as C.I. Disperse Red 1 (DR1). Second harmonic generation (SHG) has been observed on poled films. The nonlinear coefficient d33 of the samples has been thus estimated about 41.2 pm/V for TIOH doped film and about 24.8 pm/V for TI doped film, with absorption correction.