Dichroic glass

Description

A type of glass that will reflect and transmit different wavelengths of light, thus visually appearing as different colors in reflected and transmitted light. Since glass is not crystalline, the dichroic effect is achieved by coating thin layers of various chemicals on the surface of clear glass. Examples of the chemicals are: zinc sulfate, magnesium fluoride, gold, copper, nickel, cobalt oxide, iron oxide, chromic oxide, or titanium dioxide. The oldest known example of dichroic glass is the Lycurgis Cup from the 4th century. It appears a dull green in reflected light and a deep wine color in transmitted light. Another example is Alexandrit glass produced in Bohemia in the early 1900s. Currently dichroic films are being used in lamps (dichroic reflector spotlight) and solar control windows (Low-E glass) for energy savings.

Synonyms and Related Terms

dicroic glass (sp); verre dichroïque (Fr.); vidro dicróico (Port.)

Hazards and Safety

Coatings may deteriorate and change over time.