Having observed that the S1 relaxation of DMAC-py-TRZ in frozen glassy matrices at low temperature is fully hindered while it is only partially hindered in viscous solvents at ambient condition, we next transitioned to an investigation of the behavior of this compound in amorphous matrices where large geometric reorganization is also likely to be hindered. Spin-coated thin films of DMAC-py-TRZ doped into PMMA at 10 wt% were first prepared (Figure ). Emission at lPL of 516 nm was observed with a ΦPL of 63.8% under a N2 atmosphere, which decreased to 58.0% upon exposure to oxygen. Biexponential decay kinetics were observed in the time-resolved PL measurements, with τp of 26.0 ns and an average τd of 4.7 µs [τ1=1.0 µs (32.6%), τ2=7.4 µs (67.4%)],