specific optic rotation

spe·cif·ic optic ro·ta·tion ([α]),

the arc through which the plane of polarized light is rotated by 1 g of a substance per milliliter of water when the length of the light path through the solution is 1 decimeter, typically using light corresponding to the D line of sodium.

spe·cif·ic op·tic ro·ta·tion

(spĕ-sif'ik op'tik rō-tā'shŭn) The arc through which the plane of polarized light is rotated by 1 g of a substance per milliliter of water when the length of the light path through the solution is 1 decimeter, typically using light corresponding to the D line of sodium.