The most common bases used in plastic scintillators are the aromatic plastics, polymers with aromatic rings as pendant groups along the polymer backbone, amongst which polyvinyltoluene (PVT) and polystyrene (PS) are the most prominent. While the base does fluoresce in the presence of ionizing radiation, its low yield and negligible transparency to its own emission make the use of fluors necessary in the construction of a practical scintillator. Aside from the aromatic plastics, the most common base is polymethylmethacrylate (PMMA), which carries two advantages over many other bases: high ultraviolet and visible light transparency and mechanical properties and higher durability with respect to brittleness.  The lack of fluorescence associated with PMMA is often compensated through the addition of an aromatic co-solvent, usually naphthalene.  A plastic scintillator based on PMMA in this way boasts transparency to its own radiation, helping to ensure uniform collection of light.
Other common bases include polyvinyl xylene (PVX) polymethyl, 2,4-dimethyl,  2,4,5-trimethyl styrenes, polyvinyl diphenyl, polyvinyl naphthalene, polyvinyl tetrahydronaphthalene, and copolymers of these and other bases.