Azobenzene vs azopyridine and matrix molar masses effect on photoinduced phenomena. (June 2019) - Bujak, Karolina
Graphical abstract: Highlights: The "guest-host" azopolyimides were prepared and characterized. Azopolyimides exhibited large modulations of SRGs up to 100 nm. The beneficial effect of higher polymer molar masses on SRGs formation was observed. Impact of endings groups on fragility parameter for polyimide matrices was observed. Abstract: To the best of our knowledge, for the first time the effect of the presence of pyridine vs benzene structure in azochromophore on thermally driven cis - trans isomerization in a solid state is presented. The influence of the molar mass of the polymer matrix, in which the chromophores were molecularly dispersed, was revealed. The poly(etherimide) with a weight-average molecular weight within the range of 2 600–33 300 g/mol was applied as a matrix. The fragility parameter of the matrices was discussed also in the context of observed relationship between cis - trans isomerization in various matrixes. Additionally, thermal back reaction from the cis to the trans -form of 4-[4-(6-hydroxyhexyloxy)phenylazo]pyridine and 4-[4-(6-hydroxyhexyloxy)phenylazo]benzene in DMF solution was investigated. The holographic grating recording was realized in the poly(etherimide) containing azopyridine of different content.