Abstract
The orientation of a monomer unit of a polystyrene molecule is specified in terms of seven orientation functions, of which five are independent in the general case. The birefringence and infrared dichroism are expressed in terms of these orientation functions. The expression for infrared dichroism is dependent on the angle which the direction of dipole moment change for the normal mode of vibration concerned makes with the axes of the molecule. Experimental possibilities for determining these orientation functions are discussed.