Synthesis and characterization of nonlinear optical polymers having quinoline-based chromophores

Abstract

We synthesized three kinds of chromophores incorporating aromatic quinoline unit as a pi-conjugated 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 d(33) value of 27 pm/V (at 1.064 mum) and EO coefficient r(33) value of 6.8 pm/V (at 1.3 mum).