What is Dichroic Glass?
Regular glass (usually clear, but not always) that has a very thin coating of metal on one or both sides. The metal reflects some colors of light and refracts the rest through the glass, allowing the viewer to see many more colors than the glass itself would allow. Different kinds of light will also create different colors when viewed through dichroic glass. The image at right, created by Janice Chesnik’s Oval Dichroic Scope ($205.00), is an excellent example of the subtle colors that dichroic glass can provide. In this case, Janice used two wheels of dichroic glass to great effect.
“Dichroic Glass” is somewhat of a misnomer since the dielectric coating that produces all the interesting colors on a piece of glass is not glass at all but a group of 15 to 45 very thin layers of metal oxides. This “stack” of thin layers has a total thickness of approximately 48 millionths of an inch to 96 millionths of an inch. The stack of materials produces an “Interference Filter” that creates the varied and unique color characteristics that we see. Since the total thickness is so minute, the filter has very little mechanical integrity of its own and must be supported on a mechanically stable substrate. Glass is the ideal candidate for this substrate. It is transparent, has adequate rigidity, is stable, withstands relatively high temperatures and is not affected by moisture, solvents or most acids. The materials producing the filter are actually more chemically stable than most glasses used for the substrate. The filter is generally as durable as the substrate it is on. Thus, what
Dichroic Glass was created for use by NASA. The glass is coated with metal oxides such as magnesium, titanium and silicon in a vacuum furnace. Dichroic glass magically reflects multiple shades of color depending on the angle from which it is viewed! The word “Dichroic” means “two colors”– referring to its transmitted color and reflected color. Dichroic coatings are high-tech optical coatings that selectively reflect away certain wavelengths (color) of light, and allow the remaining wavelengths to transmit through. This same effect is seen in nature (peacock feathers, opals, etc.). Dichroic is not inexpensive: it can run $100 to $200 per square foot!
Dichroic Glass is a multi layer coating placed on glass by using a highly technical vacuum deposition process. Quartz Crystal and Metal Oxides are Vaporized with an electron beam gun in an airless vacuum chamber and the vapor then floats upward and attaches then condenses on the surface of the glass in the form of a crystal structure. Our colors have as many as 30 layers of these materials yet the thickness of the total coating is approximately 35 millionths of an inch. The coating that is created is very similar to a gemstone and by careful control in thickness, different colors are obtained. Thus, all our coatings are created using the same exact materials. Originally created for the Aerospace industry, Dichroic Glass is now made available to the artist community through Coatings By Sandberg, Inc. CBS Dichroic Glass is specifically designed to be hotworked in any way but can also be used in its raw form. The main characteristic of Dichroic Glass is that it has a transmitted color and
Dichroic glass, also called fusion glass, is glass treated with various metal oxides to make it appear to have many colors. Developed for use in the American space program, dichroic glass is now popular as a jewelry and art material. The name comes from a Greek word meaning “two colors.” In the 20th century, the National Aeronautics and Space Administration (NASA) began experimenting with treated glass to make astronaut face-plates that would block harmful spectrums of light. The developed process created dichroic glass, which uses fine layers of metal oxides to fracture and separate lightwaves. The resulting substance is used on a variety of objects, such as satellite mirrors and scientific instruments. It is also found on commercial products such as mirrors and camcorder lenses. To make dichroic glass, the glass must be sprayed with micro-layers of metals, usually including titanium, chromium, gold, zirconium, and aluminum. This is conducted in a vacuum chamber, which evaporates the
