Stratilat M. Cross-linked polyurethanes as active media for a solid-state laser element doped with phenalenone dyes

The thesis is devoted to the synthesis of cross-linked polyurethane containing reactive phenalenone dyes and to the investigation of the influence of chemical structure on photo-optical properties of the compositions that can be used as an active solid-state laser elements based on organic dyes. Main results were obtained with use of research methods: IR-, NMR-, UV-, visible spectroscopy, differential calorimetry, electron paramagnetic resonance, dynamic mechanical analysis, wide-angle X-ray analysis, light microscopy.It is shown that depending on the structure of phenalenone dyes and their reactivity two types of PU-compositions can be obtained: one of them contains the dye which is covalently bonded to the polymer and another one does unbounded dye. The influence of nature of hydroxyl containing oligomers and diisocyanates of initial PU on transparency, polarity function, and beam strength was studied. It was shown that PU based on ODA 800 and HMDI has optimal characteristics such as transparency (260-2200 nm) polarity function (F=0.5584), and beam strength. The study of obtained PU-compositions with incorporated phenalenone dyes has shown that their optical properties and photo-stability are strongly depended on the polarity function of initial PU. The aliphatic diisocyanate based PU was shown to be more polar that leads to an increase in the dye Stokes shift, a decrease of luminescence quenching, and growth of photo-stability of active laser element. The data obtained demonstrate the perspective of effective application of PU-compositions based on aliphatic diisocyanate with incorporated phenalenone dyes in laser technology.