title: Enhanced thermal stability of dipole alignment in inorganic-organic hybrid films containing benzothiazole chromophore.
abstract: A new thermally stable second-order nonlinear optical (NLO) inorganic-organic hybrid film was successfully prepared by using a sol-gel process of alkoxysilane dye containing a benzothiazole unit. The dye-bonded precursor was synthesized from 3-isocyanatopropyltriethoxysilane and the heterocycle azo dye 2-[4'-(N-ethyl-N-2-hydroxyethyl)-amino-phenylazo]-6-nitrobenzothiazole (EHNBT) via a urethane reaction. Molecular structural characterization for the resultant was achieved by elemental analysis, FTIR, UV-visible spectra, and 1H NMR. The second harmonic coefficients (d33) of poled hybrid films measured by a Maker fringe technique were in the range 15.9-72.1 pm/V at a wavelength of 1064 nm, depending on the concentration of alkoxysilane dye. The hybrid films containing the benzothiazole moiety exhibited higher thermal stability of dipole alignment at elevated temperatures than their analogues with a benzene ring. The d33 value of the poled film remained at 94% of its initial value after heating at 120 degrees C for 6 h, and only 18% decayed in 15 min at 180 degrees C. The result indicates that the hybrid film is suitable for the fabrication of an electro-optic device.
authors.affiliation: Department of Materials Science and Engineering, State Key Lab of Silicon Materials, Zhejiang University, Hangzhou 310027, PR China.
authors.forename: Yuanjing
authors.initials: Y
authors.lastname: Cui
authors.forename: Guodong
authors.initials: G
authors.lastname: Qian
authors.forename: Lujian
authors.initials: L
authors.lastname: Chen
authors.forename: Zhiyu
authors.initials: Z
authors.lastname: Wang
authors.forename: Junkuo
authors.initials: J
authors.lastname: Gao
authors.forename: Minquan
authors.initials: M
authors.lastname: Wang