We present a fabrication process for 3D printing of glass sensors directly onto the end of optical fiber tips. Compared to conventional polymeric 3D-printed fiber-tip sensors, our method provides far superior chemical resistance and mechanical durability. We demonstrate the utility of our sensors by reliably measuring the refractive index of aggressive organic solvents - environments where polymer-based sensors are prone to swelling and deformation. This breakthrough opens new avenues for deploying robust glass sensors in demanding industrial settings, such as chemical processing plants and oil refineries, where precise and durable refractive index measurements are essential.