Endex™ hydrocarbon resins are made from purified aromatic monomers selected to produce a resin with an unusually high glass transition temperature and softening point. Due to these unique properties Endex™ resins are especially suited for use as modifiers for the end-blocks of styrenic block copolymers. Since Endex™ resins have a higher glass transition temperature and softening point than styrene they act to reinforce compounds based on block copolymers, giving them higher cohesive strength and resistance to high temperatures. Endex™ hydrocarbon resins are water-white in color and extremely stable against thermal and oxidative degradation. Since Endex™ resins associate only with the non-elastic styrenic portions of a block copolymer they normally do not impart tack properties.