Keep it in the glass bottles and freezer, but as needed, transfer 500 ml or so to smaller glass bottles (I use 2 oz/60 ml bottles). Keep the small bottles in the freezer, too. The idea is that you do not warm a large bottle and introduce oxygen every few days to mix new juice. Open the large bottle once to transfer to smaller bottles, and open them once to mix a new batch of juice.
Strong juice (72 mg/ml) carries a responsibility. Label it well; get a lockable box and label the box before you put high-nic base in a food-oriented freezer. Include disposal instructions and a MSDS, just in case that the next person who needs to deal with the contents is unfamiliar with the risks of nicotine. I put my nicotine base away each time assuming that I will be the next person to deal with it. This is obviously unrealistic, because someday it will be someone else, maybe someone I care about.