Final answer:
Persistent glow is the term used to describe the phenomenon of glowing that continues after radiation exposure ceases. It is observed when atoms or molecules release their stored excitation energy slowly.
Step-by-step explanation:
When glowing occurs after radiation exposure ceases, it is called persistent glow. This phenomenon is observed when atoms or molecules are excited to metastable states and release their stored excitation energy slowly, resulting in a continued emission of light. Glow-in-the-dark materials, such as luminous dials on watches and toys, are examples of substances that exhibit persistent glow.