Photochromic glass
is glass that changes color when exposed to radiation. For example, spectacles
with glasses, which darken when illuminated, and again become colorless in the
absence of intense illumination, are now widespread. Such glasses are used to
protect highly glazed buildings from the sun and to maintain constant
illumination of rooms, as well as in transport.
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| Photochromic Lenses for Glasses |
Photochromic
glasses contain B2O3 boron oxide and the light-sensitive
component is AgCl silver chloride in the presence of copper (I) Cu2O
oxide. When lighting, the process occurs:
AgCl + [hν
(light)] → Ag0 + Cl0
The release of
atomic silver leads to darkening of the glass. In the dark, the reaction
proceeds in the opposite direction. Copper oxide (I) plays the role of a kind
of catalyst.
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| Smart (Electrochromic) Glass |
With intense
irradiation of glass (including laboratory) with γ-rays, neutrons, and to a
lesser extent α- and β-rays, glass also stains (most often in dark and black
colors). This is due to a change in the structure of glass and the formation of
ions, which play the role of “color centers”. When the glass is heated to
temperatures close to the softening temperature, the color disappears.
Sometimes such glasses are used as dosimeters of large doses of radiation.
