| BillyGoat |
A strict reading says the target is "one sheathed or slung weapon".
Arrows are ammunition, not weapons (but can be affected by many of the same things, such as weapon enhancements). They're listed separately from weapons (not classified as simple, martial, or exotic, with their own table to buy from). The rules for magical weapons treat ammunition as separate-but-equivalent for most purposes (see the section "Ranged weapons and ammunition" under Weapon Special Abilities in Ultimate Equipment).
Therefore, the strictest interpretation is that it wouldn't work.
The next-strictest reading is that the target is singular. Therefore, if you allow that arrows "may as well be weapons", then the spell would only affect a single arrow per casting.
For my table, I'd allow the spell to work on a full quiver. However, the RAW says "no", for the reasons presented above.