Synthesis and properties of novel Y-type nonlinear optical polyimides with high thermal stability of second harmonic generation

Authors

  • Ga-Young Lee,

    Corresponding author
    1. Department of Chemistry, Institute of Functional Materials, Inje University, 607 Obang-dong, Gimhae 621-749, Korea
    • Department of Chemistry, Institute of Functional Materials, Inje University, 607 Obang-dong, Gimhae 621-749, Korea
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  • Han-Na Jang,

    1. Department of Chemistry, Institute of Functional Materials, Inje University, 607 Obang-dong, Gimhae 621-749, Korea
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  • Ju-Yeon Lee

    1. Department of Chemistry, Institute of Functional Materials, Inje University, 607 Obang-dong, Gimhae 621-749, Korea
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Abstract

2,4-Bis-(3,4-dicarboxyphenylcarboxyethoxy)-1-(2,2-dicyanovinyl)benzene dianhydride (4) was prepared and reacted with 4,4′-oxydianiline, 4,4′-diaminobenzanilide and 4,4′-(hexafluoroisopropylidene)dianiline to yield novel Y-type polyimides 5-7 containing 2,4-dioxybenzylidenemalononitrile groups as nonlinear optical (NLO) chromophores, which constitute parts of the polymer backbone. The resulting polyimides 5-7 are soluble in polar solvents such as dimethylsulfoxide and N,N-dimethylformamide. Polymers 5-7 showed a thermal stability up to 330 °C in thermogravimetric analysis thermograms with Tg values obtained from differential scanning calorimetry thermograms in the range 179–194 °C. The second harmonic generation (SHG) coefficients (d33) of poled polymer films at the 1064 nm fundamental wavelength were around 5.56 × 10−9 esu. The dipole alignment exhibited exceptionally high thermal stability even at 20 °C higher than the glass-transition temperature there was no SHG decay below 215 °C because of the partial main-chain character of polymer structure, which is acceptable for NLO device applications. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 3078–3087, 2008

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