Stayglow is a phosphorescent material used in knife production to make handle scales or blades. It makes knives are easier to see in the dark and easier to find if they are dropped or lost. Stayglow needs an external light source to be charged.
Since the early 2000s, Stayglow has been used to make special handle scales or blades. The material was first used for Swiss Army knives. Although phosphorescent handle scales are now available for other types of knives, thanks to Stayglow, multi-tool folding knives are still the main application for this material. Stayglow handle scales are offered by a number of renowned knife manufacturers.
Stayglow is phosphorescent. A substance or material is phosphorescent if it keeps glowing for a certain time after being illuminated by an external light source. A substance becomes phosphorescent by means of a process called radiating deactivation. The atoms and molecules of the substance release excess energy in the form of light. Stayglow can be charged by exposure to daylight or artificial light. By day, this material has a milky white look; in the dark, it shines light green or blue.
The exact color depends on the nature of the used material. In the dark, Stayglow remains phosphorescent for several hours, though the light intensity diminishes over time. Stayglow knife handles are used for knives that must be usable in the dark even without an external light source. A lost Stayglow knife can be found quickly. Most Stayglow handle scales are used for hunting and outdoor knives, especially for folding knives and multi-tool folding knives.
For these knife types, it is particularly important to be able to see them in the dark, e.g. to make sure that the correct knife or tool is unfolded.