Mobility of DR1 molecules embedded in nanostructured PMMA films

The kinetics of the orientation of Disperse Red 1 (DR1) molecules embedded in nanostructured Polymethylmetacrylate (PMMA) films was studied under the effect of an intense constant electric poling field. The changes in the orientation distribution of the DR1 molecules were followed by Second Harmonic Generation (SHG) measurements. The SHG signal was recorded as function of time at three different temperatures. We focused on both, the signal increases under the presence of the poling field and the signal decays without the poling field. The studied PMMA films were nanostructured by the incorporation of ionic surfactants as the Sodium Dodecyl Sulfate (SDS) and the Cetyl Trimethyl Ammonium Bromide (CTAB) during their preparation. The kinds of nanostructures obtained in the films were determined by means of X-ray diffraction (XRD) measurements. Substantial differences in signal intensity and in growth and decay rates between amorphous and nanostructured films were found.