Probing the rotational disorder of molecules in plastic bicyclo[2.2.1]hept-2-ene with implanted muons

We report on μSR radical experiments on bicyclo[2.2.1]hept-2-ene, which demonstrate a dramatic change in the reorientational dynamics of the molecules throughout the plastic mesophase. The data might be related to some “order parameter” which is large at low temperature, while it is reduced almost by an order of magnitude (though it is still non-zero) close to the melting point.