Bleach and chlorinating liquid will last a lot longer at colder temperatures. See the table at the bottom of this page for a table of half-life vs. concentration and temperature. As for freezing, because of the salt and hypochlorite ions the freezing point for 12% chlorinating liquid is around 5ºF while for 6% bleach it is 19ºF so if you are expecting colder temperatures you should be concerned about the contents freezing and bursting the bottles. It won't expand until it freezes.