**Phosphorescence of fiberglass fleece** I tested different materials in terms of phosphorescence. A well known material is zinc sulfide doped with other metals. An other material is europium doped strontium aluminate. Both materials have one thing in common. Corner-sharing polyeders. Glass has corner-linked polyeders too. Thus I took a piece of a fiberglass fleece and held it under a black light lamp. Then I went into my dark windowless bathroom and held it against the white tiles. The fiberglass fleece seemed to glow! I took another piece of a fiberglass fleece and repeated the procedure. This piece of a fiberglass fleece glowed too. I folded the piece several times to amplify the glow. With success! First I held the glow for a faint reflection of light from somewhere. The color of the glow is red. A night light from a stack of small fiberglass mats is an application! Could the finish on the glass fiber fleece cause the phosphorescence? Generally, yes. But I removed the finish by vigorously heating the fleece. The phosphorescence of the now very soft fleece remained unchanged! I also found a triboluminescence of the folded fleece which I put into a small plastic bag. But I tested other types of microfibers too. Fibers made of cellulose, viscose and polyester. I charged up these microfibers by friction electricity and exposured them to ultraviolet light. The fibers generated yellow and red light after I switched of the ultraviolet light! So I had an idea in 2020. Electrons on the surface of the microfibers arrange themselves in clusters (crystals). When they divide into smaller clusters and single electrons they emit light in the visible range!