The synthesis and properties of nonlinear optical polyquinonediimine containing mono-azobenzene group in the side chain

Polyquinonediimines (PQDI) which have stable structure on heat and contains mono-azobenzene in the side chain were synthesized by means of condensation polymerization under TiCl4. The synthesized monomers and polymers were identified by FTIR, H-1-NMR, and elementary analysis. Especially, PQDI was comfirmed by the double-bonding peak of >C=N appeared near 1625 cm(-1) by means of FT-IR spectrum. PQDI containing mono-azobenzene group in both side chains was not soluble in non-polar solvents at all but partially soluble in the polar solvents having small dielectric constant, and dissolved in the strong acid such as sulfuric acid and CH3SO3H. Molecular weight distribution of PQDI measured by GPC showed 1.74. It was confirmed through X-ray diffraction analysis that the polymer was partially crystalline at the low angle region, but amorphous after heat treatment at 125 degreesC. The glass transition temperature (T-g) of synthesized polymer was measured as 125 degreesC by differential scanning calorimetry. The SHG value for chi ((2)) after poling at 125 degreesC was 8.6 pm/V (lambda = 1.542 mum). The SHG value slowly decreased with time from the start but appeared temporal stability after 100 hours.