The name of the substance that makes a glow stick glow is chemiluminescence. Chemiluminescence is a chemical reaction that produces light. In the case of glow sticks, the chemical reaction is between hydrogen peroxide and a fluorescent dye. When the two chemicals come into contact, they react to produce light energy. The fluorescent dye then absorbs this light energy and re-emits it as visible light, which is what makes the glow stick glow.