Amorphous photochromic films for near-field optical recording

A dithienylethene derivative having bulky substituents, 1,2-bis(5-(2,4-diphenylphenyl)-2,4-dimethyl-3-thienyl)perfluorocyclopentene (1a) was synthesized in an attempt to prepare photochromic amorphous films. la formed a stable bulk amorphous state at room temperature and the glass transition temperature was observed at 82degreesC. The conversion ratio from la to the closed-ring isomer (1b) upon irradiation with 303 nm light was as high as 73% in the amorphous film. Rewritable photon-mode near-field optical recording was demonstrated with the amorphous thin film of 1b.