Photochromic diarylethenes for photonic devices

This paper reports on a new type of photochromic compounds, diarylethenes with heterocyclic rings, for photonic devices. The diarylethenes undergo thermally irreversible and fatigue resistant photochromic reactions. The coloration/decoloration cycles can be repeated more than 7 x 10(4) times and both isomers are stable for more than three months at 80 degrees C. The response time is very fast; coloration/decoloration processes finish in less than 10 ps. Furthermore, some of diarylethenes, such as 1,2-bis(2, 4-dimethyl-3-thienyl)perfluorocyclopentene and 1,2-bis(2-methyl-3-thienyl)perflurocyclopentene, were found to undergo photochromic reactions in the single crystalline phase. Applications of the diarylethenes to optical memory media and photo-optical switching devices are now under way.