The orientational order was studied for melt-state poly(L-lactic acid) under an external direct-current electric field. A birefringence as high as 1.1 x 10(-2) was recorded against an external field of 1.0 W/m at 190 degreesC. The evidence proved that a field-dipole interaction transferred from a randomly coiled conformation to a uniaxially drawn conformation. The field-induced birefringence was temporally resolved, and the chain orientation and relaxation processes on the order of 100 s were observed in a real timescale after the field was turned on and off. A mechanism of chain orientation was examined with respect to the orientation polarization and viscoelasticity. (C) 2004 Wiley Periodicals, Inc.