Effect of methanol on optical property of irradiated poly(methyl methacrylate)

The effect of methanol on optical property of irradiated poly(methyl methacrylate) (PMMA) has been investigated. The gamma irradiation enhances the methanol transport in PMMA. The activation energies of diffusivity for case I and velocity for case II decreases with increasing gamma ray dose. For the same wavelength, in the range 350–800 nm, the transmittance decreases with increasig gamma ray dose. The equation of transmittance I with gamma ray dose ? at the wavelength 405 nm is I = I₀ exp(?0.06?^1/2), where I₀ is the transmittance of virgin PMMA. When the irradiated PMMA is immersed into methanol bath, the yellow color fades out gradually. The recovery of transmittance increases with methanol content in irradiated PMMA. The boundary to separate the outer region (solvent affected zone) from the inner region (no solvent-affected zone) is also studied. The rate of boundary movement increases with gamma ray dose.