Well, it's finally finished.
Here are the colours I tried:
Aqua (the brightest glow)
Yellow (looks pale green)
Orange #1 (deep orange, almost red)
Violet (glow is faint but lasts a long time)
Orange #2 (a much lighter orange but glow time is less)
Red (glow time is _very_ short)
I decided to make the prototype with Aqua, Yellow, Blue, Orange #1, Violet and White.
Yellow was too similar to green so I used Aqua instead of green. Red had the shortest glow time so I didn't use it. Basically I tried to maximize the glow time and the prototype will glow for at least 20 minutes and some colours will last much longer.
The prototype has white foam pads. White is necessary to improve the glow effect on the black plastic. I supposed I could try to make a white plastic cube glow but it seems easier to paint the pads first, then stick them to the cube.
Each pad is coated with a sealant to protect the glow layer from handling.
So I now have a glowing cube with 6 different colours which are all distinctive. Keep in mind that 4 of the colours will not be visible in normal light, only in the dark. Yellow and Orange are visible in regular light. The cube can be charged with fluorescent light in 10 minutes.
I tried to take a picture of the cube when glowing but my old Kodak DC215 can't manage it.
I am offering this new glow cube to twisty readers for $40 including air mail shipping world-wide. As usual you can paypal me at firstname.lastname@example.org
Please specify if you want foam pads or plastic pads.
I still have enough materials to make 10 more of the original glow cube with numbers. You can see it here http://cubeman.org/cubesell.html
Sandy has a better picture on twisty. Price is $15 which includes postage.
Also for people who need extra cubes for custom projections I still have some promo cubes, both black plastic and white plastic $10 _including_ shipping world-wide. If you need more than one please email me first. Use a hair dryer to get the stickers off and then use rubbing alcohol to remove the adhesive.