The frequency-dependence of the viscoelastic shear modulus at low freq
uencies in a lamellar polystyrene-polyisoprene block copolymer is qual
itatively identical to that measured in small-molecule smectics, namel
y, the rodlike 4-cyano-4'-octylbiphenyl and the flexible n-nonyl-1-O-b
eta-D-glucopyranoside. All three materials were studied after quenchin
g from the isotropic state, and during and after alignment by large-am
plitude oscillatory shearing. The kinetics of aligning, as measured by
changes in moduli during shearing, are similar, despite great differe
nces in molecular characteristics. These moduli and the aligning proce
ss are evidently controlled by smectic fluctuations and defects, the d
ynamics of which have universal features.