The effect of thin films on the orientational and optical properties of nonpolar monolayer smectogen 4-butoxyphenyl-4'-decyloxybenzoate ((10) over barO (4) over bar) liquid crystal has been studied by polarizing microscopy and high-resolution photon transmission method. The uniform planar textures of (10) over barO (4) over bar on the surfaces coated with WO3, VO2, and WO3-VO2 mixture thin films have been obtained. No significant shifts in the phase transition temperatures to lower values under the influence of the surfaces have been observed. We have also presented the new experimental data on the critical behavior of the layer compression modulus B near the nematic-smectic A transition. It was observed that the data in the vicinity of the transition can be described by a power law expression after the introduction of a first-order correction-to-scaling term within the limit of experimental error. The resulting critical exponent was found to be 0.34 -/+ 0.01 which is good agreement with the previously reported values for other investigated compounds in literature.