Saturday, July 11, 2009

Glowing in the Dark

Objects that glow in the dark have always fascinated me. There are some mysterious and magical qualities in the chemical and physical properties going on. For those of us who live in the 21st century where everything plugs in or runs on batteries, we expect to have to turn on a switch to have something light up.

During one of my courses at Corning, the instructor, James Nowak, made an off-hand comment about glow in the dark glass. We pressed for details and were treated to a wonderful demo. Sure enough, once the demo piece was complete and annealed, we took it out in the sunlight for a minute or two. Upon moving back inside, even though it was lighted and not really dark, it was clear that the piece was glowing a deep green color! Fantastic! Cool! And whatever other adjectives apply to this amazing idea.

This is actually a little harder than it sounds. First, you need some special "glow in the dark" power. This can be obtained from Glow, Inc. I got the
Ultra Green v10 Glow in the Dark Powder and the Ultra Blue Glow in the Dark Powder. Based on the rating system on the website, the "Ultra Green V10" is the brightest and longest lasting. The "Ultra Blue Glow" is the next brightest. The rest seemed pretty weak in comparison.

Most people would expect to just roll the hot glass in the powder to coat the glass. That doesn't work. The glow powder doesn't melt, even at the hot glass temperatures of over 2000 degrees Farenheit. It just rolls right off. Pretty tough stuff. The solution we used is to create a little cup, put a teaspoon or two of the powder in the cup, and seal the cup with hot glass.
This takes two people to do effectively. In order to spread the glow uniformly throughout a blown glass object, you need to gather over the cup a few times to get the mass of glass you want to use. Then repeated stretching, folding, twisting, and bending are needed to distribute the powder. Since the powder is melted, you are attempting to encapsulate a few grains of powder into little pockets all through the piece.

The picture above was taken indoors in a completely dark room and a photoflood spotlight used to "charge" the vase for about 10 minutes. The piece can be charged in sunlight, even an overcast day, in a few seconds, but a bright light takes a lot longer. My windows get bright sunlight but the glass panes must block out a lot of the UV spectrum as that is what is required to excite the glow powder. I need to create a simple base with a small UV black light as that works well to charge the glow particles.

Here is a picture of the vase in normal light. The glow glass is the base color and then coated in black. The black was sandblasted away to expose the glow layer.

I've made some great marbles with this technique, however I haven't got any pictures to post. See the "1000 Objects - More or Less" post for the reasons behind that sorry tale.

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