Synthesis, photochromism and holographic optical recording of a photochromic diarylethene bearing fluorine atoms

A symmetrical photochromic diarylethene, 1,2-bis[5-(3,5-difluorophenyl)-2-methyl-3-thienyl]-3,3,4,4,5,5-hexafluorocyclopent- 1-ene (1a), was synthesized, and its photochromic and fluorescent properties were also investigated. The results showed that this compound exhibited reversible photochromism, changing from colorless to blue after irradiation with UV light both in solution and in PMMA amorphous film. In hexane solution, the open-ring isomer of the diarylethene 1 exhibited relatively strong fluorescence at 350 nm when excited at 280 nm. The fluorescence intensity decreased along with the photochromism upon irradiation with 297 nm light and its closed-ring isomer showed almost no fluorescence. Using diarylethene 1 as recording medium, polarization holographic optical recording was carried out successfully.