Have you ever wondered about the meaning of Dichroic (di – kro’ – ik) glass and how it is made?
NASA developed dichroic glass for use in satellite mirrors. Dichroic glass is a multi-layer coating placed on either black or clear glass 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. Some colors have many of these layers, yet the thickness of the total coating is approximately 35 millionths of an inch.
Dichroic coatings transmit certain wavelengths of light, while reflecting others, thus creating a similar effect like the iridescence observed in fire opal, dragonfly wings and hummingbird feathers.
Dichroic glass has two primary colors and many other secondary colors. The transmitted color is seen when holding the glass directly at a light and the reflected color is seen when the glass is placed against a dark background. As the glass is moved around, many other colors will be seen.
The resulting plate of dichroic glass can then be fused with other glass in multiple firings. Certain wavelengths of light will either pass through or be reflected, causing an array of color to be visible. Due to variations in the firing process, individual results can never be exactly reproduced; each piece of fused dichroic glass is unique.
With the play of light together with its vibrant color, dichroic glass is a prime tool used to add interest to any project. Since there are many different colors, patterns, and textures, glass artists have unlimited design opportunities. I love using dichroic glass to make pendants and earrings. I will usually put a piece of clear glass over the top of the dichroic and fuse it in my kiln. Finally, I will attach a bail and it is ready to wear!