Do glass or polymer transmits the radiation?
There is not a simple answer since it will always depend on the last use and working conditions of the system. Usually speaking glass fibers are better suited for that environment and for data transmission where high temperatures are constant. Glass fibers are extremely thin conductors only some microns in diameter, therefore to construct a sizeable light conductor, even thousands or hundreds have to be sheathed and bunched together.
Bending radii are small and the performance is acceptable even though glass fibers with comparable spectral characteristics to PMMA are significantly more expensive. In essence both, polymer and glass systems have drawbacks and advantages, to be individually assessed in view of the real application and working conditions. However, in current times, there seems to be a general trend to abandon glass fiber optics into lighting applications in favour of PMMA.