Evaluating polyimides as lightguide materials

摘要: Lightguides were fabricated from three commercial polyimides of which one contains and the others contain two hexafluoroisopropylidene (6F) groups. The latter are isomers using either para or meta isomer same diamine. As number 6F groups increases optical losses corresponding lightguides decreases. In thick containing polyimides, loss values below 0.1 dB/cm can be realized optimized conditions. Two mechanisms—ordering with without charge transfer complex formation voids pinholes—are seen to responsible for losses. second type reduced by cure optimization. Where ordering is possible annealing leads increased Geometrical restraint ordering, however, reduction in otherwise identical Losses observed bulk always higher than top bottom layers polyimide films.