I have heard of using protective gases, even your exhaled breath, to cut down on the oxygen exposure of film developers. But this is a great idea.
I keep my opened Rodinal in the fridge, next to the beer, and I fill the bottle with glass marbles, to
cut down on the O2 that eats the Rodinal.
This wine bag/boxes would be good for this as well, but Rodinal comes in such small quantities, this is a fine option.