The segmental orientation behavior of the thermoplastic elastomer [poly(butylene terephthalate-co-tetramethylene oxide)] is studied with infrared dichroism and polarizing microscope. The orientation function of soft segment is observed to be distinctively different from that of hard segment. It is rationalized with the difference in the glass transition temperatures of soft and hard segments which are about -80 and 45$^{circ}C$, respectively. The birefringences observed through the polarizing microscope as a function of draw ratio resemble the orientation functions of hard segments. It is explained in terms of the n electrons in hard segment with affect the refractive index more strongly than o and non-bonded electrons.