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Stories about: photochromic materials

Color-Changing Material Leads to New Type of Sunglasses Photochromic materials are a class of substances that can usually change colors when they are exposed to the direct influence of certain wavelengths of light. They can most commonly be found in the lenses of sunglasses, or even in spectacles that change their color from transparent to black or brown when exposed to i... 28 April 2009 19:01 GMT