The most important thing to remember about dichroic glass is that the glass itself is not dichroic. Glass does not produce color; it was the 'layers' of micro-thin sheets of various oxides and quartz that are applied to the glass surface.
This creates an 'interference filter' which acts to either reflect or transmit light depending on the oxide used, coating thickness, and other such factors. This particular glass is also popular for making Dichroic Glass jewelry.
Creating a dichroic glass is a four-step process.
First, the glass is cleaned thoroughly in a clean environment which, depending on its eventual use, it could take up to four cleansings to make glass meet technical specifications. The smallest bit of dirt, fingerprints or where water may have undesirable effects on the glass.
After the glass is cleaned, the second step takes place – the glass is placed in a furnace or a vacuum chamber containing an electron gun and a container or containers in which the metal oxide deposited.
Water is pumped out, pressing the pressure inside the chamber and at the right time, the electron gun is activated, the evaporation of the oxide. Evaporating oxide will condense and attach to any surface in the chamber – especially glass.
After the desired oxide thickness is reached, the electron gun is turned off and new oxide positioned for use, if needed. This process is repeated until the desired thickness of the layer – or planned color – is reached.