While fluorescending materials are only glowing as long as there exists a source of light, phosphorescending materials are glowing after they are no longer exposed to a light source. The phosphorescending pigments needs to be placed into a carrier material for using it. The carrier material could be materials as varnishes or thermoplastics.
An important condition for a long lasting and highly after glowing is a preferably transparent or translucent substrate. The after glowing is depending on the following parameters:
excitation light and duration
concentration of the pigments
low-light-level conditions in the environment
point-of-view, that is the degree of eye-adaptation to the dark
body color of the carrier material
Compared to the production of zinc sulfide based pigments, strontium-aluminate based pigments are light-resistant and resistant against graying. The phosphorescending pigments are very hard and have a value of 9 on the Mohs scale of mineral hardness comparing to a diamond with a value of 10. Furthermore they are temperature-stable above 500° Celsius.