We recently demonstrated that the dielectric permittivity of a single-layer SrTiO3 thin film decreases with increasing thickness, and that incorporation of intermediate AlFeO3 layers into an SrTiO3 /AlFeO3 heterostructure mitigates this suppression of dielectric properties. We proposed two temperature-dependent mechanisms that could contribute to this effect: thermal strain and the formation of polar nanoregions (PNRs). In this study, we used Raman spectroscopy to assess the possibility of PNR formation in single-layer SrTiO3 films (50 and 250 nm thick) and in a multilayer heterostructure 5×[50 nm SrTiO3 + 50 nm AlFeO3. Our results show that the spectra of SrTiO3-containing structures exhibit telltale signs of PNR formation: the presence of symmetry-forbidden first-order modes and an asymmetric shape of the TO2 mode.