Compatibility Testing - Polarized Lens Test

One way of testing fused glass for compatibility is to use the Polarized lens test. Think of it as using light to figure out if your glass is incompatible. First off you need to get two polarized lenses (2 pieces of polarized film will do). You can buy polarized film from a glass supplier. Next fuse the together the warm glass you will be testing.

Once fused put the glass between the two pieces of polarized film and hold it over a light source. When you are holding all three pieces over a light source make sure to rotate the lenses/film so they are at right angles to each other. Now make sure that as little light shines through as humanely possible. Or inhumanely possible if you happen to be an interstellar glass artist.

Now all you have to do is look for a white glow at the edges of where the different glasses come together. If there is little or no glow than your fused glass is compatible. If there is a significant amount of glow than "Houston we have a problem". The more light glowing around the edges means the greater the incompatibility.