We give two alternative proofs of the invariance of the Drinfeld pairing under the action of the braid group. One uses the Shapovalov form, and the other uses a characterization of the universal $R$-matrix.
"Invariance of the Drinfeld Pairing of a Quantum Group." Tokyo J. Math. 39 (3) 885 - 900, March 2017. https://doi.org/10.3836/tjm/1475723090