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Colored micron-sized methyl methacrylate particles have been obtained by dispersion polymerization of methyl methacrylate and an azo-monomer in the presence of vinyl silane oxazoline macromonomer used as stabilizer. The polymerizable dye has a methacryloyl group for copolymerization and suitable azobenzene moiety to improve the solubility in the solvent. The particles showed a spherical morphology and large size distribution, features which were appreciated by scanning electron microscopy. The azo-dye could be covalently incorporated up to 4 wt% in the particles. The thermal properties of the particles were investigated by simultaneous DSC-TGA analysis. The particles showed clear Tgs at 128 °C and thermal stability up to 292 °C. The copolymer's chemical structures were confirmed by 1H-NMR and FT-IR spectroscopy and their average molecular weights were evaluated by SEC.

In this paper we present a series of side-chain polymers bearing original azo-moieties, namely: poly(methacrylate)s and poly(maleimide-styrene)s; designed for nonlinear optics (NLO). The different classes of azopolymers are discussed comparatively to one another from the point of view of: solubility, molar weights, glass transition temperatures & thermal stability, chromophore contents, and as well as from the point of view of their third-nonlinear response. The third-order nonlinear absorptive and refractive effect of the polymers containing different substituted azobenzene chromophores were investigated by the Z-scan technique. The effect of substituents on the azobenzene group and the composition of the polymer chain were investigated by UV-Vis spectroscopy.

We report the synthesis of five new hybrid polymeric structures obtained by free radical copolymerization of some organic azo-based methacrylate m onomers and 3-methacryloxypropyl trim ethoxysilane (MEMO). The copolymers are soluble in common solvents like methylene chloride, chloroform, dichlorbenzene, dimethylsulfoxide, dimethylformamide. The copolymeric structures might be interesting from the point of view of nonlinear optical response due to a rich content in chromophoric units determined by H-NMR spectroscopy. The structures were also characterized by FT-IR spectrosc opy, TGA and SEC analysis. Keywords : azobenzene, MEMO, hybrid, methacr ylate monomers, NLO, copolymers. 1. INTRODUCTION During the last two decades, material s such as chemically or physically modified PMMA matrix with organic dyes were investigated for their SHG /THG nonlinear optical response 1-5 . The "classic" PMMA matrix alone proved not to be a very good media for chromophores, allowing a fast relaxation of the oriented dipoles after removing the electric field