A thiophene-vinyl conjugated FTC-type chromophore was synthesized and reacted with 3-isocyanatopropyltriethoxysilane to form alkoxysilane dye. The structure of alkoxysilane dye was confirmed via elemental analysis, FTIR and (1)H NMR. Stable and transparent hybrid films were fabricated following sol-gel process of alkoxysilane dye and tetraethoxysilane. The second harmonic generation coefficients (d(33)) of the hybrid films were measured via in situ second harmonic generation measurement. The d(33) value of hybrid films was calculated to be 43 pm V(-1) when the chromophore loading density was 20 molt Furthermore, the thermal stability of optical nonlinearity was also investigated through a depoling experiment, showing a half decay temperature of 165 degrees C. (C) 2011 Elsevier B.V. All rights reserved.