My Glasses Change Faster Than Yours.

My glasses transition into sunglasses when I walk outside and I am always asked about them. This pair of glasses takes a little while to transition and the speed is dependent on the amount of sunlight. Well, researchers at the University of Washington, in Seattle, are working on "smart" sunglasses that transition from light to dark by command using a watch battery. You can find the story at http://pubs.acs.org/cen/science/85/8515sci1.html under the title "Smart Sunglasses From Electrochromic Materials." Traditional sunglasses are made with tinted glass, a polycarbonate material, and transition lenses like mine are made with photochromic materials and are very slow. The "smart" prototype is made using an electrochromic polymer that lightens or darkens in one second and uses a few miliwatts of power. The transition here occurs with the press of a button on the sidearm of the eyewear.

Once dark, the glasses block 99% of a wavelength that represents yellow light. This is a big step in optics because other models require more voltage, more transition time, and more power to maintain color change. However, some researchers caution that the eyewear can be heavy and Chunye Xu states that his prototype has several layers sandwiched between two indium tin oxide-coated glass pieces. Polymers have also been created that turn red or green but prototypes have not yet been made. Xu is working further by creating a more compact circuitry and incorporating vision correction features into the smart glasses. Imagine how popular I would be if my glasses transitioned in one second.