PHYSICAL AGING AND LIGHT-SCATTERING OF LOW-LOSS POLY(METHYL METHACRYLATE) GLASS

Isothermal aging has been carried out on low-loss poly(methyl methacry late) (PMMA) glass at 18 degrees C below the glass transition temperat ure (T-g). The effect of enthalpy relaxation on light scattering loss of PMMA glass which had no excess scattering was investigated by the u se of differential scanning calorimeter (DSC) and light scattering mea surement. The light scattering intensity of PMMA glass did not increas e with increasing aging time. It is seen that the light scattering los s of glassy PMMA is not affected inherently by physical aging as a res ult of its approach to thermodynamic equilibrium at a temperature 18 d egrees C below its T-g.