| 초록 |
3,4-Bis-(3,4-dicarboxyphenylcarboxyethoxy)-4’-nitrostilbene dianhydride (4) was prepared and reacted with the corresponding aromatic diamine to yield unprecedented Y-type polyimides 5-8 containing 3,4-dioxynitrostilbenyl groups as NLO-chromophores, which constituted parts of the polymer backbones. The resulting polyimides 5-8 are soluble in polar solvents such as DMF and DMSO. Polymers 5-8 showed a thermal stability up to 320 oC in TGA thermograms with Tg values obtained from DSC thermograms in the range 143-164 oC. The second harmonic generation (SHG) coefficients (d33) of poled polymer films at the 1064 nm fundamental wavelength were around 9.45 x 10-18 C. The dipole alignment exhibited exceptionally high thermal stability even at 30 oC higher than Tg, and there was no SHG decay below 180-190 oC because of the partial main chain character of polymer structure, which is acceptable for nonlinear optical device applications. |
