Because people have a need to glue things to other things
Plastic to GlassFor the strongest, fastest, and most invisible bond we recommend:
For a non-toxic but not so strong alternative we recommend:
Whenever you are gluing glass you must consider the visibility of the adhesive. If the glass is translucent or transparent, you will want a glue that dries as clear as possible.
There are so many kinds of plastic its hard to give advice here that applies to them all. If possible try a small test in an area that doesn't show.
Before gluing any glass bond be sure that the glass is clean, free of any oil (even from your fingers) and dry.
Some plastics have a smooth surface finish that can be sanded off with a 120 grit sand paper, for better adhering properties.