We report a study of excited-state lifetimes of the phosphorescent organometallic complex Ir(ppy)3 on ensemble and a single-molecule level. With decreasing concentration, an increasingly intense fast component of 3 ns lifetime appears next to the 1.1 mus phosphorescence. Experimental evidence suggests that strong two-photon absorption followed by fluorescence is responsible for the fast lifetime component.

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Cationic polymerizations of various vinyl ethers with cyclic substituents were performed with BF 3 OEt 2 . The polymers had relatively high molecular weight (M n : 18,900-132,000), although the polymerization of phenyl vinyl ether did not proceed. According to differential scanning calorimetry, the obtained poly(vinyl ether)s showed higher glass transition temperatures than room temperature. These poly(vinyl ether)s gave free-standing membranes both by a solution-casting method and by a hot-press method. In the membranes prepared by solution-casting, the oxygen permeability coefficients of these membranes were in the range of 0.81-6.01 barrers, and poly(2-adamanthyl vinyl ether) showed the highest gas permeability among them. Gas permeability of the membranes prepared by hot-press was lower than that of the membranes prepared by solution-casting.

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