Photoinduced orientational ordering in the series of methacrylic azopolymers

• Published in: Polymer Science. Series A Vol. 52; no. 3; pp. 261 - 271
• Main Authors: Nadtoka, O. N., Yaroshchuk, O. V., Bednaya, T. V., Ol’khovik, L. A., Syromyatnikov, V. G.
• Format: Journal Article
• Language: English
• Published: Dordrecht SP MAIK Nauka/Interperiodica 01.03.2010; Springer; Springer Nature B.V
• Subjects: Anisotropy; Applied sciences; Azo; Chemistry; Chemistry and Materials Science; Exact sciences and technology; Excitation; Fragments; Homology; Order disorder; Orientation; Physicochemistry of polymers; Polarization; Polymer Sciences; Polymers and radiations; Properties and characterization; Structure and Properties; Polymer Science Series; Orientational Order; Orientational Order Parameter; Copoly Mers; Orientational Relaxation; Substituent effect; Methacrylate polymer; Composition effect; Photoinduced effect; Experimental study; Methyl methacrylate copolymer; Azo compound; Orientational order; Free radical polymerization; Side chain; Light sensitive polymer; Order parameter; Optical properties; Preparation; Birefringence; Time curve; Light sensitive copolymer; Methacrylate copolymer; Radical copolymerization
• ISSN: 0965-545X; 1757-1820; 1555-6107
• DOI: 10.1134/S0965545X10030077

Polymethacrylates with side azo fragments containing various end substituents and spacers are synthesized and characterized. Spatial ordering of azo fragments in the series of the synthesized azo polymers under the action of polarized excitation light is studied by the methods of null ellipsometry and polarization spectroscopy. Two types of anisotropy development during photoirradiation are found. In homologs with strong acceptor substituents of azo fragments, biaxial orientational structure can be observed; as the radiation dose is increased, this structure is transformed into a uniaxial structure with a negative order parameter and with an axis parallel to the polarization vector of the excitation light. In this structure, the maximum degree of orientational order is achieved in polymers with high concentrations of azo fragments. In homologs with donor substituents of azo fragments, the initial stages of irradiation likewise lead to the development of biaxial orientation; later, this orientation is transformed into an isotropic distribution. The mode of anisotropy development is controlled by the lifetime of photoisomers of azo fragments.