Abstract
Second-order nonlinear optical (NLO) materials have attracted interest because of their potential applications in optoelectronic technology. In this work, conjugated and non-conjugated backbone NLO polymers were prepared by nitrogenation reaction from PCZ and PVK. EA analysis shows the two NLO polymers contained approximate nitro ratio. In preliminary study, PCzNO2 had higher SH intensity in corona field. Therefore, second harmonic property may become stronger by adding donor-acceptor substitution to pi-conjugate polymers. A new strategy for self-polymerization performed on chromophore has been explored to develop 2,7-carbazole-based NLO polymer with a high density of chromophores. It had excellent solubility in common organic solvents, such as THF, DMSO, DMF and NMP, etc. The DSC thermograms of polymer exhibited a glass transition (Tg) at about 140 °C. After poling, large second harmonic coefficients of 45.6 pm/V was found for PCzCCSO2. Fast relaxation of the effective SH coefficient was observed at temperatures higher than 110 ℃. The temporal stability was investigated by tracing the second harmonic coefficient as functions of temperature and time, respectively. It remained 76% over 200 h at 85℃.