We disclose a monovinylarene/conjugated diene block copolymer, comprising: (i) a random (conjugated dieneX/monovinylareney)m block, wherein x is about 2.5 wt% to about 10 wt%, y is from about 90 wt% to about 97.5 wt%, and x + y is about 97.5 wt% to 100 wt%; and (ii) a (conjugated dime)n block; wherein n is from about 20 wt% to about 30 wt%, m is from about 70 wt% to about 80 wt%, and m + n is from about 90 wt% to 100 wt%. We also disclose a method of forming the block copolymer and a method for fabricating an article from the block copolymer. The block copolymer typically exhibits a Tg at least about 10°C less than the Tg of a reference polymer differing only in that x is about 0 wt% and y is about 100 wt%.