Synthesis and Characterization of Nonlinear Optical Polymers Having Quinoline-based Chromophores

We synthesized three kinds of chromophores incorporating aromatic quinoline unit as a <TEX>π-conjugated</TEX> bridge in order to prepare more thermally stable nonlinear optical (NLO) chromophores than general stilbene unit. The NLO poly(methylmethacrylate) copolymer, polyimides, and polyester were successfully synthesized by these corresponding quinoline-based monomers. Their physical and optical properties were investigated by thermogravimetry, gel permeation chromatography, ultraviolet-visible spectroscopy, second harmonic generation (SHG) and electro-optic (EO) measurement. All the polymers exhibited better thermal stability,however their NLO activity was a little lower than that of general stilbene-based NLO polymers. Among three kinds of polymers, the PMMA copolymer with quinoline chromophores had the largest SHG coefficient d33 value of 27 pm/V (at 1.064 <TEX>)</TEX> and EO coefficient r33 value of 6.8 pm/V (at 1.3 <TEX></TEX>).