The mystery of color sunglasses

Many car drivers often wear a pair of dark oakley sunglasses cheap when driving. When driving a car in the Sun or snow days, this pair of dark sunglasses to protect his eyes from the glare of the stimulus for a long time. However, when a car suddenly adopts towards the dark time, wears black sunglasses instead turned into a liability. For a while, pick, it is so convenient. What a good way to lift the driver of this dilemma?
There are. Wear color sunglasses. In the Sun, it is a pair of black sunglasses, thick black sunglasses and stopped the Sun. In the soft light of the room, it becomes just as ordinary sunglasses, transparent colorless.
Mysteries of the photochromic sunglasses in the glass. This special glass called "photochromic" glass. In its manufacturing process, mixed into a light-sensitive material in advance, such as silver chloride of silver and Australia (collectively referred to as silver halide), there is a small amount of copper oxide catalyst. Lenses from no color to a light gray, dark brown, black sunglasses back to the sound flux from sunglasses, is the magic of silver halides ". In photochromic sunglasses in the glass, there are changes in exposure is very similar to Imaging and photographic films. Decomposition of silver halide light, multitudes of black particles of silver, evenly distributed in glass, glass lens look bleak, movement against light, this is the dark sunglasses. However, and not on a photographic film, decomposition of silver halides of silver atoms and halogen atoms have been generated, still tightly close together. When you are back in a slightly darker place, facilitated by copper oxide catalyst, silver and halogen combination again, generate a silver halide, glass lenses become transparent again.
Permanent Mission of silver halide in the glass, decomposition and combination of response repeated ad infinitum. Photographic films and printing papers can only be used once, photochromic sunglasses can keep using it. Photochromic sunglasses not only as the light intensity dimming out also can absorb harmful UV on the eye, the sunglasses in the top grade. Photochromic glass window glass for glazing, when sunny, Sun room could not be shot; when a cloudy day or in the morning, evening, outdoor light is obscured, Interior remains clear. As if fan window by hanging up sunshade curtains. Some top-end hotels, restaurants, color changing glass has been installed. On the window of the cab of the vehicle and tour buses that photochromic glass, in direct sunlight