Dichroic (die-cro-ick) glass literally means 'two-coloured", derived from the Greek "di" for two and "chroma" for colour. It is so-named for its multi-coloured, reflective properties.
Dichroic glass has a fire and brilliance all of its own. It has been adapted from aerospace technology for the world of art. It costs around $3000 a square metre. NASA orginally developed dichroic glass for use in satellite mirrors in the early 1990s, and also for use for re-entry tiles on space shuttles.
We buy in dichroic glass sheets. Making it is a complex process, made only by a handful of manufacturers that have highly specialised equipment: high temperature vacuum chambers, vaporizing electron guns, and high temperature kilns. The intense, computerised process involves vaporising metallic oxides, such as magnesium and titanium, with an electron gun. Once vaporised into floating dust, it settles on and coats the surface of hot glass inside a vacuum chamber. The complete process may require from 15 to 45 different layers, each layer being less than one millionth of an inch thick.
The type, order applied and number of metallic oxide layers used will determine the final appearance of the glass. Once the coating process is complete, the whole piece is kiln fired at a high temperature, fusing the oxides to the glass.
Dichroic glass appears to have more than one colour at the same time when viewed at different angles - two, sometimes three or four!
This reflective phenomenon is known as thin-film physics (the same reason you are able to see floating colours from oil on water).
The dichroic coating does not have its own inherent colour, but rather it blends light to reflect colours exactly as a prism makes rainbows. What you see reflected is pure, coloured, light energy.
With imagination and creativity the possibilities are endless for incredibly rich and varied combinations of colours and designs.
Making dichroic glass really is rocket science, but exploring its endless possibilities is an art!