From a quick web search:
The chemicals used to create this reaction in glow sticks are usually hydrogen peroxide and a mixture of phenyl oxalate ester and the fluorescent dye that gives the glow stick its color. The hydrogen peroxide is contained in a small glass tube that floats within the mixture inside the plastic glow stick. This is why you must bend a glow stick to make it start glowing. When the stick bends, the glass vial breaks, the hydrogen peroxide is released, the chemical reaction begins and you get the distinctive glow.
I can't think that the peroxide would hurt the leather but I would probably want to research more on the phenyl oxalate ester. Also, anything containing the word "dye" would scare me a bit.
Good luck.