Photoexcited 7-hydroxy-8-(N-morpholinomethyl)quinoline (HMMQ) has previously been shown to transform from the excited enol form E* into the excited keto form K* in a number of consecutive elementary processes involving formation of an excited zwitterionic form Z* and rotational Brownian motion of the morpholino group which acts as a proton carrier and gets Into motion only if its initial intramolecular H-bond is broken thermally. The latter motion is not restricted to cases in which HMMQ is dissolved in polar solvents, but may proceed also in nonpolar media which contain proton accepting solvents such as 1,4-dioxane. Molecular dynamics simulations of the motion of the morpholino group in the forms E and Z* in liquid cyclohexane and in liquid 1,4-dioxane are presented. The simulation of Z* in cyclohexane reveals that an intramolecular hydrogen bond between the protonated N atom in the morpholino group and the deprotonated O atom inhibits the rotational motion of the proton carrier during the whole period of simulation. In the case of Z* in 1,4-dioxane, an intermolecular H-bond is formed at the expense of the intramolecular hydrogen bond and then the protonated carrier drags the solvent molecule along its path in the rotational Brownian motion. The main conclusions are summarized at the end of the publication.