SYNCHROTRON SMALL-ANGLE X-RAY-SCATTERING OF SLOW SPINODAL DECOMPOSITION IN A BLOCK-COPOLYMER

A block copolymer poly(styrene-b-tert-butylstyrene) in the frozen ''di sordered'' state has been prepared by fast solution casting. The time changes in the scattered intensity induced by a temperature jump from the frozen disordered state at room temperature to above the glass tra nsition temperature were measured by using time-resolved synchrotron s mall-angle X-ray scattering. It was found that the time changes in the scattered intensity could be approximated by the Cahn linearized theo ry. The wavenumber q-dependence of the Onsager coefficient, Lambda(q), derived from the growth rate, R(q), was discussed.