Glow in the dark zip ties are a popular way to identify wire and cable in the dark. They rely on phosphorescent additives that absorb light and glow in the dark for hours afterward. Once the glow diminishes, they can re-absorb light and glow again.
Most modern glow-in-the-dark items, such as my son’s glow-in-the-dark yo-yo and ball, use safe non-radioactive phosphors like zinc sulfide or strontium aluminate. Older products, such as some watches, used radioactive phosphors such as radium (which has a half-life of 1600 years) or promethium which has a much shorter period of time.
Some products also use fluorescent materials which fluoresce under ultraviolet (UV) light, making them very visible in low or dark conditions. These types of zip ties are typically UL recognized and CSA approved and they are available in many different colors.