Pick the right variety of Glow in the dark products
The Glow in the dark Evolution
Photoluminescent materials have come a long way since it's introduction as a 'glow in the dark' substance. The concept of "glow-in-the-dark" effect is not new. We have all noticed the glowing stars painted on kid's bedroom ceilings somewhere or the other. Traditionally, these glow staffs would have been produced using zinc sulfide pigments doped with copper and would exhibit a pale yellow/green body color and when the light source is removed it would exhibit a bright yellow-green afterglow. The afterglow which was initially bright starts fading soon and after an hour it is almost gone. Thus from a commercial point of view such pigments were limited to screen printing purpose due to the particle size of the zinc sulfide crystals.
The Glow Chemistry
But today Glow in the dark or Phosphorescent pigments, as it is sometimes technically referred to, is a new kind of rechargeable luminous product produced from rare earth alkaline aluminate / silicate activated by rare earth ions. Crystals of strontium aluminate (SrAl2O4) and barium aluminate (BaAl2O4) are promising host materials for long afterglow luminescence especially when doped with Europium . These are not the traditional Zinc Sulfide. The difference is quite remarkable.
The structure of the pigment particle is basically crystalline, which has a amazing capacity of absorbing, storing, and emitting light. The crystals absorb any ambient light, including regular indoor light. The after-glow of Phosphorescent pigments or paints are at least ten times stronger than Zinc Sulfide powder especially when the pigment is Strontium based. And it is worth mentioning that the duration of the afterglow of these photoluminescent pigments is much longer that Zinc Sulfide pigments - even in some cases it is as long as 10 to 12 hours.
This provides a huge potential in industrial, defense, safety and art-novelty applications like glow sticks.
So while choosing Glow in the dark pigment or paint, make sure you buy the new type of Phosphorescent Glow-in-the-dark paints or pigments or any other products made from them like glow sticks, glow paints etc.
Salient Properties of photoluminescent Glow in the dark Paints and Pigments
1. Non toxic and non radioactive.
2. Gets activated quickly even in indoor lighting conditions.
3. Longer, brighter after-glow.
4. Shelf life of more than 12 years.
5. Comes in at least a dozen of different glow colors.
6. Weather ( water and heat) resistant.
8. Water-based and non-water based available.
9. Applicable on almost all types of surfaces.
10. Very suitable for Glow in the Dark art and Craft projects.