Iris glass
Iris glass ( iridescent glass) is transparent, colorless or colored glass that shimmers in beautiful rainbow colors .
It can be obtained by introducing the still hot objects as they come from the glass furnace into a room which is filled with vapors evolving from a heated mixture of barium nitrate , strontium nitrate and stannous chloride . Historically, an iron vessel was used for this purpose, the bottom of which was heated by a coal fire and the hinged lid had an opening for the neck of the glassmaker's pipe . The action of the vapors should only last a few seconds.
Iodine vapors and certain types of glass can also be used to make glass iridescent by heating it with water containing around 15 percent hydrochloric acid under a pressure of 200 to 500 kPa. By changing the chemicals and the temperature one should be able to change the colors in which the glass is iridescent. Most suitable crystal glass , Hyalithglas and the semi-saturated color glasses to represent Iris glass . The same was first portrayed by Zahn in Hungary in 1872 . An iridescent glaze can be created on pottery by applying potassium earth glaze with the addition of aluminum platinum chloride .
During the Art Nouveau era, iris glass was also widely used in glass mosaics . A specialized production facility was the Klostermühle glassworks in Unterreichenstein , founded in 1836 , where work continued until 1947.
Antique glasses, as they are known from archeology , are iridescent due to their storage. The iridescence in this case is caused by the porous surface of the glass and the penetration of foreign particles into it. When the find was in use, it was mostly not iridescent.
Iridescent glass is particularly common under Roman glasses, but especially rarely under Celtic glasses, as these are characterized by an extraordinarily smooth, solid surface.
supporting documents
- ↑ Otto Dammer: Handbuch der inorganic Chemie, Stuttgart 1893, p. 155.