Photoisomerization behavior and photoinduced surface relief gratings on azopolymer film by a monochromatic light irradiation

Liquid crystalline azobenzene functionalized polymer, P3AB6Ac has been synthesized and its photoisomerization and holographic properties have been studied. The liquid crystalline properties of the polymer were confirmed by differential scanning calorimetry and optical polarizing microscopy. The polymer showed reversible photoisomerization in both solution and in the film. Surface relief gratings were induced on the polymer films prepared by spin-coating from its solution in THF by the irradiation of linearly polarized and circularly polarized Ar+ laser individually through photomask. The surface relief structures were investigated using atomic force microscopy. A surface grating with a surface modulation depth of 400–500 nm was obtained by irradiation of circularly polarized Ar+ laser for 30 min. The period of record of the polymer film was also found to be considerably high, more than one year.