In this article, the authors will present a simple way to produce thin solid organic films, with a content of more than 60 wt% photoactive molecules dispersed in a polymeric matrix showing an almost complete and fully reversible photoisomerization. These high filling factors could be achieved by using branched side chains in the molecules, which prevent crystallization. The chromophores were codissolved with the polymer Polymethylmethacrylate (PMMA) of different M (w) in toluene in various concentrations and spin casted onto the substrate. The effect of the M-w of PMMA on the switching kinetics and the agglomeration tendency of different molecule configurations were investigated.