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Polymer blends along with 1-(4-methylphenyl)-3-(4-N,N, dimethyl amino phenyl)-2-propen-1-one (MPDMAPP) NLO-chromophore-doped composite films were prepared by solvent casting method using DMF. The optical properties were studied using UV-visible, refractive index, steady state fluorescence, and fluorescence microscopic imaging techniques. The UV-vis absorption spectra showed three absorption bands and were assigned to localized n ? p*, n ? p* inter band, and p ? p* transition of charge transfer groups. The observed changes in the absorption peak, edges, and intensity with dopant concentration are understood based on charge transfer complex (CTC) formation. The refractive indices of the composite films varied from 1.4937-1.5398 for red and 1.5165-1.5516 for green light respectively. The steady state fluorescence data showed both emission peak wavelengths and intensity changes with MPDMAPP doping level in blend. The fluorescence anisotropy (r) variations in the composite films indicate the suppressed molecular motion of MPDMAPP in the solid composite film. The fluorescence microscopic image of these composite films showed that the films are photochromatic in nature. These modified properties are thought to be due to the charge transfer upon excitation from the donor to the acceptor connected through benzene ring and CTC formation. POLYM. ENG. SCI.,

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The optical, electrical, and microstructurtal properties of pure and TiO 2 /Poly(vinyl alcohol) (PVA) composite polymer films were carried out using FTIR, XRD, UV-Visible, DC electrical conductivity, and Positron annihilation lifetime spectroscopy (PALS) techniques. The FTIR study reveals that the Ti 1 ions of TiO 2 interacts with the OH groups of PVA via intra/inter molecular hydrogen bonding and forms charge transfer complex (CTC). These formed CTC will affect the optical property of the composite film, which is reflected from UV-Visible study. Using the observed UV-Visible spectra, optical energy band gap is estimated and its value decreases with increasing dopant concentration. The positron annihilation studies show that the considerable effect on free volume related microstructure of the PVA due to doping and complex formation. These microstructural modifications are also enhances PVA crystallinity which is reflected from XRD studies. It is also observed that the TiO 2 particle forms cluster within the PVA due to the aggregation of particles and these particle cluster size increases with dopant concentration. These microstructural variations due to doping affects the DC electrical conductivity and its variations are understood based on the intra chain one-dimensional interpolaron hopping conduction mechanism. POLYM. COMPOS., 37:987-997, 2016.