Try a silicone adhesive, such as Devcon. This adhered well to a %100 soft silicone rubber part I needed to glue onto some insoles.
Use 100% silicone adhesive like PL700.
Silicone.
Any silicone based glue will bond to silicone rubber. -Aqua Seal, Seal All, Goop, Plumber's Goop, Gloozit, PL premium to name just a few that will work.
I would use one of the silicone glues like Plumbers Goop or 100% Silicone for this.
This depends on the use but Krazr (super) glue or silicone type bond would work. Rubber and glass will expand and contract at different rates so the adhesion may not last. Fish tank sealant is very strong and can be bought on line.
Silicone will do that.
Silicone would work for that.
Silicone adhesive
Silicone.
It's a silicone based glue, that will bond leather and rubber. 'Shoe Goo' is very good.
Silicone is best for that.
Use a silicone glue like Plumber's Goop or Gloozit.