A hydrocarbon polymer modifier comprising a cyclic component, wherein the hydrocarbon polymer modifier has a glass transition temperature and number average molecular weight that is represented by Tg≥95−2.2*(% H Ar) and Tg≥−53+(0.265*Mn), an aromatic proton content (% H Ar) of from 12 mole % to 19 mole %, and an Mn of from 300 g/mole to 450 g/mole, wherein Tg is the glass transition temperature expressed in ° C., % H Ar is the content of aromatic protons of the hydrocarbon polymer modifier, Mn represents the number average molecular weight of the hydrocarbon polymer modifier, and the cyclic component is selected from the group of a distillation cut from a petroleum refinery stream, and/or C4, C5 or C6 cyclic olefins and mixtures thereof.