Conformational relaxation of poly(methyl methacrylate) has been investigated by measuring the temperature dispersion of dynamic viscoelastic functions and the density under systematic thermal histories. Samples were quenched from various temperatures (T-Q) in the course of slow cooling through the glass transition temperature (T-g). The tan delta curves of samples quenched from T-Q < T-g agreed with that of the slow-cooled sample in a temperature range above T-Q. Densities of the samples at 30 degrees C were consistent to thermal histories. Segmental conformation is successively frozen from large to small scale of segmental motion during slow cooling.