Influence of PCBM on the Glass Transition Temperature (<i>T</i>_g) of Poly(<i>N</i>-Vinylcarbazole)-Based Photorefractive Composite

Abstract

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 C61 butyric acid methyl ester (PCBM) was fabricated. The influence of PCBM on the glass transition temperature (Tg) of the photorefractive composite was studied using a differential scanning calorimetric (DSC) method. The active energy of glass transition (Eg) 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 Tg of PVK - based PR composite polymers. The Tg first increase and then went down with the PCBM content (below 1.0 wt %) increasing. The possible cause of the influence of PCBM on Tg was proposed.