I felt the same way but ended up freezing in plastic. However, one thing I did try was freezing the milk in silicone ice trays and then transferring the ice cubes to a glass container. There are a lot of different ice cube trays that you could use that are not plastic.
I use mason jars (4oz and 8oz) with plastic lids. To defrost I put them under running water until it warms up, then I put in a bowl of hot water. Straight in hot water cracks the glass.
I use the evenflo glass bottles. Yes, I have at least 50 of them and a deep freeze so it works for me. They are pretty cheap, probably as cheap or cheaper than mason jars, so I invested in a bunch of them with DS1 and have used them again with DS2. A word of warning, you will break one or two along the way and lose some milk, but for me it is worth it to avoid plastic.
I've been wondering about the same thing, for the same reason. I was thinking about trying Comotomo silicone bottles - less likelihood of breakage, non plastic, but at $24 for a 2-pk, pricey. I thought I would get a few of these and try them out along with some glass bottles (like the Evenflow ones mentioned above) and see what works best for a reasonable cost.
I use 8oz mason jars, they really only hold 7ozs because you have to leave room for it to expand as it freezes. I think they're $8 for 12. We try to remember to pull one out and put it in the fridge the day before, or use warm water to help it thaw. If you do mason jars, keep the cardboard box they come in to keep them organized in the freezer.
Re: Freezing breast milk in glass