The guys that get glow-in-the-dark heads from me are very partial to red, purple, and white(natural). Why, I can't explain. Never fished them to give any first hand experience. But the guys that do certainly have their favorite colors.
I know the purple glow looks more on the light blue side when illuminating (to my eyes).
Don't have many requests for chartreuse green glow, which surprises me - maybe it's a location thing.(?)