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

The main goal of this research was to verify if some advantages could be ob tained by the replacement of poly(1-vinylcarbazole), a component commonly e mployed for organic photorefractive materials, with various polymers contai ning sidechain heteroaromatic moieties. For this purpose, poly(1-vinylpyrro le), poly(1-vinylindole), and some methyl-substituted compounds of poly(1-v inylindole) were considered. The best conditions for both monomer synthesis and polymerization were found. A first possible advantage of the new polym eric 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 photo refractive behavior at room temperature. In addition, the verified higher e lectric dipole moments of the pyrrole and indole derivatives could improve the compatibility of the optically nonlinear component, required in the sys tem, typically an ate-molecule, by increasing its solubility inside the ble nd. All the synthesized vinyl monomers and polymers gave clear spectroscopi c evidence of the formation of charge-transfer complexes with 2,4,7-trinitr ofluorenylidenmalonitrile, an efficient sensitizer for photoconductivity. ( C) 2000 John Wiley & Sons, Inc.