Dichroic glass

‘Dichroic glass’ is really a misnomer. The dichroic part is actually a very thin film of metal oxides which are too thin to stand alone and have therefore been layered onto a sheet of glass which acts as a substrate to lend the thin film strength. Dichroic glass is any glass that is coated with metallic oxides such as silicon, titanium and magnesium in a vacuum furnace using a technology called thin-film physics. Dichroic means 'two colors' and the glass is called this because it reflects one color but transmits another.

Dichroic glass is a high-tech spin-off of the space industry. "Dichroic" is defined as the property of having more than one colour, especially when viewed from different angles or from transmitted to reflected light. Hence dichroic glass is also referred to as "chameleon glass". For example, a particular formulation will appear blue, but shift the dichroic glass slightly and the color will transition to green.

Dichroic coated glass is produced by a process called "thin film physics" and is generally referred to as a colour separator. It's normally used as an interference filter in scientific measuring or correcting applications. It is transparent, has adequate rigidity, is stable, withstands relatively high temperatures, and is not affected by moisture, solvents or most acids.

Manufacturing Process

Dichroic Glass is made by applying a surface coating of one or more layers of transparent materials designed to create reflections of a specific wavelength in order to modify an optical effect. The coating itself is completely transparent. Dichroic glass can provide very crisp and vibrant colors.

The most commonly used coating materials are titanium oxides, zirconium oxides, silicon oxides and aluminum oxides. They are applied using a method called Vapour Deposition. The deposition occurs in a high vacuum chamber where the glass is suspended in the top of the chamber and rotated. The coating materials are placed in crucibles at the bottom of the chamber and bombarded with an electron beam that is focused and swept over the materials with electromagnetic fields. The heat generated by the bombardment vaporizes the materials, and the vapour condenses on the glass suspended above.

Dichroic coatings create some of the purest and most brilliant colours ever seen in glass. They are fragile and must be protected from abrasion unless they are reheated too close to the softening point. Once heated in this way, the coating becomes very durable. The resulting colour of the glass depends on the sequence of the many layers of coatings. Incredibly, the total thickness of the multi coatings is only between 3 to 5 millionths of an inch. It is a highly technical computerized manufacturing process.

The resulting Dichroic Glass is totally unlike normal coloured glass where light enters and part of the colour spectrum is absorbed, leaving the part not absorbed to be reflected. With Dichoric Glass all light entering is either transmitted or reflected (“dichromatic" means "two-colored"). These two sources have completely different colours, and importantly, the colours alter as the angle of view is changed. This results in fascinating and beautifully vibrant colours.

With the play of light together with its vibrant colour, Dichroic Glass is a prime tool used to add interest to any piece of work or project. With over 45 colours of dichroic doatings available that can be placed on “any” substrate (i.e glass), artists have unlimited freedom of expression.

Architectural Applications

There is an ever growing demand for the use of dichroic glass in architecture. Its resilience to weather and never-fading colors are prime material to enhance office buildings, custom homes, walkways, fountains, skylights, walls, lighting fixtures and more. Dichroic glass is also used in windows and curtain walls. Dichroic glass windows on the external wall maximize the entry of natural daylight.

In Other Industries

Dichroic Glass was originally created for the aerospace industry for satellite mirrors, but it now has many technical uses including lighting, fibre optics, infrared lasers, motion picture equipment, and more.