Cycloaliphatic-aromatic polyimides based on diamines with azobenzene unit

A new family of functionalized semiaromatic polyimides has been developed. Cycloaliphatic-aromatic polyimides, derived from the polycondensation of 1,2,3,4-cyclopentanetetracarboxylic dianhydride (CPDA) with various diamines bearing azobenzene group, have been prepared and characterized. Molecular structural characterization for the resulting polymers has been achieved by ¹³C NMR, ¹H NMR, FTIR and UV-visible spectroscopies. Light-induced optical anisotropy, in novel azobenzene functionalized polyimides, has been studied by holographic polarization grating recording performed at 514.5 nm line of Ar⁺ laser. Two-wave mixing technique has been employed to inscribe the gratings in these polymers. Formation of gratings has been investigated with two s-s and s-p polarized writing beams. The kinetics of grating recording observed within the studied polymers is discussed in relation to their structure.