In this work, we report on the investigation of photoexcited states in conjugated polymer (donor) - fullerene (acceptor) interpenetrating networks (polythiophene derivatives - PC61BM) embedded into conventional polymer hosts like polystyrene, polyvinylcarbazole, polycarbonate or polyvinylbenzenechloride, using photoinduced FT-IR spectroscopy. We discuss the influence of specific host polymer matrices on photoexcited states of the photoactive guests via photoinduced infrared activated (IRAV) modes