Effect of the processes of orientation of nonlinear optical fragments of aside chain in comb-shaped polymers of the methacrylic series on the second-harmonic generation in thin films

New comblike copolymers of methacrylic acid esters with an optically nonlin ear chromophore-a derivative of the 4'-(4-nitrobenzylideneamino)phenol-in a side chain were obtained. Processes of forced orientation of nonlinear opt ical chromophores covalently bonded with the main chains in an electric fie ld and the effects of the conditions of orientation on the nonlinear second -order optical activity of the polymer films were studied in some detail. T he existence of a correlation between the chemical structure and the compos ition of the copolymers with the magnitude and the stability of the surface electron potential of the corresponding films was shown. It was establishe d that a maximum extent of orientation of chromophores in the bulk of the p olymer and, as a consequence, a high intensity of the second-harmonic signa l were achieved when the thickness of the region of the uniform electric fi eld maximally approached the thickness of the sample. (C) 2001 MAIK "Nauka/ Interperiodica".