That’s what I figured from your question, it “feels” like plastic, it’s lightweight and it’s flexible, thus it “must” be plastic. Of course a digitizer glass cannot be just 100% glass even if most part of it, it is indeed. Infact it’s a sandwich of different layers and materials with on top typically a protective film. For more info on various build types you could have a look here: https://www.eizoglobal.com/library/basics/basic_understanding_of_touch_panel/