FIG. 3.

(a) Schematic of the local shear stress fields induced by local bending along a wavy surface. (b) Normalized average stress ($\langle \widehat{\sigma }\rangle /\langle {\widehat{\sigma }}_0\rangle$) applied to PS films (h_f = 31 nm) as a function of t, showing the relaxation of the wrinkle pattern at various T below T_g. The solid lines are stretched exponential fits. (c) Average relaxation time (τ: circles) and high frequency Young’s modulus (E_f: triangles) for PS films (h_f = 31 nm) as a function of T. The vertical dotted line indicates the bulk T_g of PS, and the inset shows the plot of stretched exponential coefficient (β) vs. T.