ScienceNOW Daily News reports that researchers have developed a material that almost instantaneously changes from clear to dark blue when exposed to ultraviolet (UV) light, and it just as quickly reverts to clear when the exposure is removed.
For more than a decade, chemical engineer Jiro Abe and colleagues at Aoyama Gakuin University in Japan have been studying the light-sensitive properties of photochromic materials, including a compound called hexaarylbiimidazole (HABI). In its natural state, HABI is colorless, but when ultraviolet light breaks one of the bonds in the molecule, it produces a version that is dark blue. They found that by adding naphthalene to the compound, they could accelerate the color change to about 180 milliseconds. Adding a compound called cyclophane instead of naphthalene improved the clear-to-blue conversion even more–to about 30 milliseconds. According to an article in the current issue of the Journal of the American Chemical Society, the cyclophane version of HABI reverts just as rapidly to its colorless state when the UV light source is turned off and the reactions can be repeated thousands of times.
Scientists see this as a great step forward in the development of optical storage drives. This could be a boon for transition lenses which take forever to change from clear to dark if they can develop ways to control it. Similar work has been ongoing for some time to protect vision from LASER as well as the flash associated with a nuclear detonation but such systems have been powered in order to make the nearly instantaneous transition.