  Sharp tip nanoindentation of glassy polymers is a constrained, localized
viscoelastoplastic deformation. We interpret this complexity, in terms of the
well-understood uniaxial deformation. From the uniaxial compression data in the
literature, for PMMA, PC and crosslinked SU-8, we obtain their universal,
yield-normalized recovery curves, with eps*=eps/eps_y, being one measure of the
corresponding strain states (CSS). Nanoindentation recovery is determined from
the 2sec constant rate unloading h-P data, modeled by a generalized power-law
(variable power exponent). Comparing these data-sets, yields the correlation
coefficient between the notional nanoindentation strain rate epsdot_N and
strain and true strain rate and strain, c=epsdot_N/epsdot_t=eps_N/eps_t. The
equivalent strain, eps, and the c value for any polymer, are within a narrow
range, from the onset of indentation. Combining residual profiles via scanning
probe microscopy with mathematical modeling of the indenter tip, provides the
strain distribution beneath the tip. CSS measures examined here, indicate
polymer-specific regions to regions common to glassy polymers, which are
reached very early in the nanoindentation.
