Cooling a glow stick slows the reaction a slightly and causes it to last longer, but the light is dimmer. This can be demonstrated by freezing an activated glow stick. When it is reheated, it will begin to glow again. However, if the chemical reaction has already occurred and the glow stick has already gone out, freezing the glow stick will not cause it to begin glowing again. A high quality glow stick will last 8-12 hours, provided there is no otherwise interference. It will glow faintly for about one day after this time period is over, however the primary glow will have gone out.
Other factors, such as the color of the glow stick (Green, yellow and orange are the brightest colors and therefore last the longest. ), the previous treatment of the glow sticks (Sometimes, a glow stick will have been accidently activated by being knocked over or bumped before the activator intends to, meaning that the chemical reaction may have already occurred by the time it is intended to be activated. ) and the amount of light they are exposed to and for how long. (Being hit with direct light damages the glow stick, lessening its longevity. )