An alternate synthetic approach for soluble nonlinear optical polyimides

Han Young Woo, Hong Ku Shim, Kwang Sup Lee, Mi Yun Jeong, Tong Kun Lim

Research output: Contribution to journalArticle

38 Citations (Scopus)

Abstract

Three functionalized second-order nonlinear optical polyimides were synthesized by the step growth polymerization reaction between a chromophore-containing dianhydride and three different diamine compounds. This alternate approach (i.e., incorporating a nonlinear chromophore into a dianhydride monomer) may avoid troublesome syntheses of the chromophore-containing diamine and can provide easy preparation of the polyimides with various chromophores. The number-average molecular weights (Mn) of final polymers determined by GPC ranged between 10 000 and 16 800 (Mw/Mn = 1.59-2.28). No melting was detected and they showed relatively low glass-transition temperatures ranging from 161 to 181 °C. They are readily soluble in aprotic polar solvents such as tetrahydrofuran, N,N-dimethylformamide, N-methylpyrrolidinone, and so forth. High optical quality films were prepared by spin casting from a 10 wt % cyclohexanone or N-methylpyrrolidinone solution. The second harmonic generation (SHG) coefficients, d33, of the polymers were determined to be 24-37 pm/V (d33(∞) = 7-10 pm/V) at a fundamental wavelength of 1064 nm. All of the poled polymer samples showed outstanding orientational stability up to 125 °C without any measurable decay of the SHG signal. In particular, the polyimide with a 4,4′-(hexafluoroisopropylidene)dianiline unit (PI-2-DANS) showed the best dynamical thermal stability of the poling-induced dipole alignment up to ca. 170 °C.

Original languageEnglish
Pages (from-to)218-226
Number of pages9
JournalChemistry of Materials
Volume11
Issue number2
DOIs
Publication statusPublished - 1999
Externally publishedYes

ASJC Scopus subject areas

  • Chemistry(all)
  • Chemical Engineering(all)
  • Materials Chemistry

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