Juice boxes freeze very nicely! I freeze them all the time to use as ice packs when packing snack bags too-- it'll keep the non-frozen ones cool and by the time it defrosts, my little one is ready for more juice/
I wouldn't put them all in the freezer at once. They can freeze too hard and take longer to defrost. If I know it's going to be needed in a few hours, just freezing it overnight is enough.
They do bulge a tiny bit, but I've never had one explode. I also freeze the juice bags-- like Capri Sun.