I don't want to give you a red X, but I disagree. Yes, almost all of mine is in glass, with polycone caps, but there appears to be little (if any) downside to storing it in PET plastic. I discovered this by accident when I found some nic I'd bought 2-1/2 years earlier that I'd forgotten about in the freezer. It was fine. I've now got an experiment going where I'm comparing storage of identical batches of nic in its original PET plastic bottles vs. rebottled in glass. It starts here: Nic Base Storage: Freezer vs. Room Temp Experiment
I agree. PET is what's used in Coke bottles. Considering the high pressure involved at times with carbonated beverages, I wouldn't be concerned about splitting or breakage with PET in a freezer.