SYSTEMATIC INVESTIGATION OF THE ANNEALING BEHAVIOR OF MAGNETOOPTICAL DISCS

A comprehensive study of the annealing behavior of magneto-optical dis c substrates was performed, offering important insight into the origin of birefringence, The lateral birefringence is a result of the flow-i nduced molecular orientation in the skin layers generated in the mold filling stage, and the cooling-induced energy-elastic stresses generat ed inside and outside the mold. Cooling-induced energy-elastic birefri ngence relaxes quickly, and consequently the flow-induced birefringenc e with a radial dependence of decrease at the outer radius becomes pre dominant after annealing below the glass transition temperature. The a nnealing behavior of the vertical birefringence follows a Kohlrausch-W illiams-Watts-type relaxation. The results serve as a predictive tool for similar substrates.