Role of the free surface in the formation of relief gratings on azo polymer films

Abstract

Efficient trans → cis → trans photoisomerizations of the azo chromophores in the bulk of the polymer along the photodriven mass transport beginning at the surface, led to the formation of surface relief grating (SRG). Restricting the free surface of the azo polymer films in a controlled manner, the formation rate and the modulation depth of the SRGs decreased.