Figure 4. Visible light exposure of the F-azo polymer films.

Ultraviolet–vis absorption spectra of the planar aligned polymer film as a function of illumination time when exposed to light of (a) 530 nm and (b) 405 nm wavelength. The UV absorption bands at 430 and 470 nm correspond to the n→π* transitions of cis and trans isomers, respectively. Photographs of the splay-oriented film after illumination by light of (c) 530 nm and (d) 405 nm wavelengths. Below the photographs in e and f are representations of the molecular order of the films showing the mesogen (grey) and the F-azo molecules (orange).