The best way to remove Plastic Restorer from glass would be to use an IPA solution. If you're wondering what an IPA solution us, it's simply a mixture of isopropyl alcohol and water (google IPA solution for detailing).
Here is one article I've found for the IPA solution: http://www.detailedimage.com/Ask-a-Pro/ask-a-pro-the-isopropyl-alcohol-ipa-wipedown/
(Using straight isopropyl alcohol should be okay too)