Nadtoka O. New methacrylic azopolymers and their phototransformations under UV-irradiation

The thesis is devoted to the synthesis and investigations of photochromic polymers and copolymers based on methacrylic azomonomers. The side chains of obtained polymers contain flexible alkyl spacers of different length and groups of the different nature. The difference in chemical structure of the side chains was expected to influence on the difference in the supramolecular structures of azobenzene moieties. Due to flexibility of alkyl spacers, the azobenzene fragments can be rotated relatively freely in the polymeric matrix. The combination of the transmission null ellipsometry and total absorption method, earlier approved for several polymer classes, is applied to study 3D orientational configurations of azochromophores in azopolymers on polymethylmethacrylate base. The dependence of the orientational configuration is observed on the structure of azochromophore fragments and the concentration of azochromophores in PMMA. Under irradiation, if reorientation mechanism of the photoinduced ordering prevails, the azochromophores are reoriented perpendicularly to the polarization direction of the exciting light, Eex, and in the saturation state they are randomly distributed in the plane perpendicular to Eex. The diminution of the azochromophore's concentration in PMMA reduces the anisotropy rate but does not influence on trends described above. The observed regularities were earlier described for several other classes of photosensitive polymers and so they may be common rules for photoordering in the photochromic media.