A capped polyindane oligomer of formula (1): (1) wherein R1, R2, and R3 are each independently hydrogen, halogen, C1-12 hydrocarbyl provided that the hydrocarbyl group is not tertiary hydrocarbyl, C1-12 hydrocarbylthio, C1-12 hydrocarbyloxy, or C2-12 halohydrocarbyloxy wherein at least two carbon atoms separate the halogen and oxygen atoms; and Rx and Ry are as provided herein.