Influence of PCBM on the Glass Transition Temperature (T_g) of Poly(N-Vinylcarbazole)-Based Photorefractive Composite

摘要

2, 5-dimethyl-(4-p-nitrophenylazo) phenetole (DMNPAPE) was synthesized. And its structure was confirmed with ultraviolet-visible (UV-vis) spectroscopy, Fourier transform infrared (FT-IR) spectra and ~1H Nuclear Magnetic Resonance (~1H NMR) spectroscopy. The photorefractive composite consist of 33 wt % poly (N-vinycarbazole) (PVK), 50 wt % 2, 5-dimethyl-(4-p-nitrophenylazo) phenetole (DMNPAPE) and 16 wt % ethyl carbazole (ECZ) doped with x wt % (≦1 wt%) [6, 6]-phenyl C_(61) butyric acid methyl ester (PCBM) was fabricated. The influence of PCBM on the glass transition temperature (T_g) of the photorefractive composite was studied using a differential scanning calorimetric (DSC) method. The active energy of glass transition (E_g) was evaluated by Kissinger's and Moynihan's relation. The analysis results indicate that the transition region shifts to higher temperatures with the increasing heating rate, and PCBM content (≦1.0 wt %) can influence T_g of PVK - based PR composite polymers. The T_g first increase and then went down with the PCBM content (below 1.0 wt %) increasing. The possible cause of the influence of PCBM on T_g was proposed.