In lyotropic liquid crystalline polymers, flow is known to induce eith
er director tumbling or flow alignment, depending on the shear rate. R
ecently the existence of an intermediate transition region, a ''waggin
g'' regime, has been predicted on the basis of molecular theories. Her
e, rheological and rheo-optical techniques have been applied to assess
the physical reality of the wagging regime in a solution of poly(benz
yl glutamate). Stationary rheological and rheo-optical characteristics
indicate a gradual change from tumbling to flow aligning when the she
ar rate is increased, without any divergent behavior in between. When
transient measurement techniques are used, however, distinct differenc
es can be observed over a very narrow shear rate range, immediately be
fore the onset of flow alignment. This intermediate region is characte
rized by strongly fluctuating transients of the stresses and the linea
r conservative dichroism, especially when starting from a flow-aligned
initial condition. In this manner evidence is provided for the existe
nce of an intermediate regime, which can be associated with the predic
ted wagging regime.