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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

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Multiple-quantum spectroscopies are reviewed in the ffame of electron paramagnetic resonance. Some properties of different nonlinear techniques are discussed for both transverse and longitudinal detection. The connections of effects recently presented with the procedure of longitudinal detection of electron paramagnetic resonance (LODESR) in presence of double transverse irradiation are stressed. Peculiarities of LODESR spectroscopy and its capabilities in facing problems related to relaxations in presence of very slow dynamic processes are evidentiated. Recent results show the vitality of the LODESR technique, that in the future could be applied to new fields, owing to experimental updating.

Abstract. Different instrumental apparatuses are presented employing disc-shaped dielectric resonators working in the Whispering Gallery Mode (WGM). The conditions suitable to take the best ffom the microwave power obtalrled from a trade klystron in the X-band have been verified for the ESR part of the experiments. It is well known that a good ESR saturation condition is an essential prerequisite to have satisfactory ENDOR results. The WGM dielectric resonators seem to be very suitable for multiple irradiation purposes and in particular for ENDOR experiments which is the aspect we wanted to exploit here. Various radiofrequency ENDOR irradiation circuits have been tested and the obtained spectra of a y-irradiated single crystal are presented and criticized. Some results for very high frequency ESR applications are also reported.