Fluorescence Upconversion by Triplet-Triplet annihilation is demonstrated in a fully polymer-integrated material, i. e., in the limit of restricted diffusion. Covalent attachement of a metal free sensitizer and an annihilator to a poly(methacrylate) backbone yielded an all-in-one system to achieve UC by TTA. The impact of polymer-integration of both UC chromophores on the UC dynamics was studied in solution by ns-time resolved transient absorption and emission.