There are two ways to make glow-in-the-dark ink. First, you can purchase the materials for a ready-made glowing ink from a craft store. If you are a beginner working at home, use that method. You can also make a glowing ink substance with chemicals in a lab. This is a science demonstration that should NOT be attempted at home. Phosphorus is very poisonous.
For home use, mix together glow powder from a craft store and ink, according to the directions on the packaging.
Choose your colour. Different colours of glowing ink will glow for different periods of time, varying from 30 minutes (purple) up to 12 hours (green).
Use a syringe to load the mixed ink into a pen or an ink cartridge, if you have mixed the powder with printer ink.
Wear protective gear appropriate for a chemistry lab, including eye goggles and gloves.
Combine phosphorus and oil of cinnamon in a small glass bottle.
Screw on the cap tightly.
Heat water in a beaker over a Bunsen burner to make a warm water bath.
Put the bottle into the warm water bath and heat until the ingredients dissolve.
Glow powder can also be added to paint.
Phosphorus is poisonous. Do NOT try the second method unless you are experienced in working safely in a lab with toxic chemicals.