Consider a DVD similar to that of Problem 5.86. To protect sensitive information within the storage medium, a very thin film of reactive polymer is embedded within the polycarbonate at a distance d = 0.5 mm from the surface. The thin film can undergo a chemical reaction with oxygen during which it is converted from a transparent material to an opaque material, rendering the information unreadable. The chemical reaction begins when the oxygen concentration at the reactive polymer reaches C _crit = 5 x 10^-5k mol/m³. The DVD is shipped in an oxygen-proof pouch; determine the elapsed time after removal from the pouch before the DVD self-destructs. The solubility and diffusivity of oxygen in polycarbonate are S = 8.9 X 10^-3 k mol/m³ ∙ bar and D_AB = 6.5 x 10^-12 m²/s. respectively.