Several years ago, I split a Sigg aluminum bottle. I partially filled it, left the cap off, and placed it at an angle in the freezer, so that when the water froze, it would not exert pressure all the way around the bottle. I thought doing so would prevent a split. I was wrong. The local store where I bought it sent it back to Sigg for me, & they replaced it.

Now, plastic bottles, on the other hand...I've used Nalgene polypro & Lexan bottles both, freezing & thawing with no problems. The plastic bottles that water comes in (such as Aqua Fina) withstand a lot of freeze/thaw cycles. We keep a couple of 1 liter bottles filled, capped, & frozen solid in our big freezer. They're used as extra ice packs that double as cold drinking water when they thaw.

I typically leave several in my truck, year round. The worst thing that's happened to any of them is that the frozen AF bottles are slightly swollen, & won't return to their original contours. They also have the advantage of being "free" (sort of...if you're buying bottled water anyway, reuse the bottles!), and easy to replace when necessary.

David