Optical transmission and surface plasmon polariton (SPP)-mediated reflection measurements have been performed on the ferroelectric liquid crystal, (s)-4-(alpha-methylheptyloxy)-4’-(4"-n-octylphenyl-oxycarbonyl)biphenyl in both surface-stabilized and non-stabilized states of the chiral smectic C phase. A comparison of the molecular response to an externally applied electric field is made between the bulk and boundary layers on the basis of changes in transmitted and reflected light intensities caused by alterations in the strength and polarity of the field. in particular, the changes in the reflected light intensity in the Kretschmann ATR prism geometry are referenced to the light intensity at the resonance of SPPs. When surface-stabilized cells are used, the switching in alignment between the bistable states is observed in the boundary layer as well as in the bulk layer, although the maximum frequency which allows the switching is an order of magnitude less for the boundary, indicating a stronger influence from the substrate surface. Very reasonably, such a switching is not observed when non-stabilized FLC cells are used. Moreover, it is found that the bulk layer exhibits a memory effect, but it is not observed in the boundary layer.