Synthesis and characterization of different poly(1-vinylindole)s for photorefractive materials

Abstract

The main goal of this research was to verify if some advantages could be obtained by the replacement of poly(1-vinylcarbazole), a component commonly employed for organic photorefractive materials, with various polymers containing side-chain heteroaromatic moieties. For this purpose, poly(1-vinylpyrrole), poly(1-vinylindole), and some methyl-substituted compounds of poly(1-vinylindole) were considered. The best conditions for both monomer synthesis and polymerization were found. A first possible advantage of the new polymeric substrates resided in the values of the glass-transition temperature, which, as expected, was constantly lower than that of poly(1-vinylcarbazole). This could lead to a material that requires the introduction of a lower quantity of plasticizer in the final photorefractive blend to display photorefractive behavior at room temperature. In addition, the verified higher electric dipole moments of the pyrrole and indole derivatives could improve the compatibility of the optically nonlinear component required in the system, typically an azo-molecule, by increasing its solubility inside the blend. All the synthesized vinyl monomers and polymers gave clear spectroscopic evidence of the formation of charge-transfer complexes with 2,4,7-trinitrofluorenylidenmalonitrile, an efficient sensitizer for photoconductivity. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 39: 253–262, 2001