If you've ever thought transition lenses were cool, researchers at Cambridge are about to change your outlook, literally.

With "Smectic A" glass, normal windows can go opaque instantly, blocking out sunlight and potentially saving millions on costs associated with heating and cooling. It could be used in vehicles, containers, and elsewhere.

The mechanism behind it is not totally dissimilar from how your LCD screen operates. In fact, "The main component of the developed composite material is made up of a type of liquid crystal known as a 'smectic' liquid crystal," explains Techxplore, "which is different than a solid crystal or a liquid. When a voltage is applied, the liquid crystal molecules all try to align themselves with the electric field, and the material they are embedded in (glass or plastic) will appear transparent."