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.