Instant Sunglasses

[Vekseid]

Transparent material rapidly turns dark blue on interacting with UV light

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When Abe's team began analyzing HABI's chemical structure through simulations and laboratory experiments, 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. Better still, Abe and colleagues report 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 compound is so stable that the reactions can be repeated thousands of times.
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Sunglasses just being the most obvious use. Selective, triggered filtration is in general pretty useful >_>

[The Overlord]

Probably going to be booku expensive at first, but having this 360 in auto glass would be pretty nice, especially here in Georgia where the sun seems to eventually get in your eyes no matter what road you're on.