polyaromatic initiators which have good absorption properties in the UV and visible region of the electromagnetic spectrum (ɛ329: 28,746 M−1 cm−1, ɛ430: 5028 M−1 cm−1). The fluorescence quantum yield was calculated as 0.025 which is slightly lower than that of the parent thioxanthone compound (φf: 0.07). The triplet lifetime was found to be 3.9 μs from laser flash photolysisstudies. The initiating efficiency