As fiber-reinforced polymers grow with respect to scientific and industrial interest, the understanding of the chemical compounds of thermoset materials becomes of high interest. Prior investigations have shown that the interface between fiber and matrix material lacks sophistication for chemical reasons. Especially carbon fibers are equipped with a weak chemical interaction between the material surfaces. Investigations have been performed focusing on the improvement of this interface by changing the ratio of the chemical compounds of the thermoset material before producing test specimen in a vat polymerization machine. Due to the layer-wise manufacturing as opposed to the aspect ratio of the fibers, they were randomly oriented along the printing layers. The fiber-matrix interface was investigated under consideration of the chemical composition of the three-component photopolymer thermoset material followed by tensile tests in order to investigate the effect of the chemical composition on the strength and modulus as indicators for the fiber-matrix interface. Moreover, scanning electron microscopy analysis and other imaging techniques were used in order to qualitatively analyze the interface.