In this study, the as-deposited and annealed fluorinated silicon dioxide (SiOF) films were coated on plastic substrate as a moisture barrier layer by the liquid phase deposition (LPD) method. Their ability of resistance to moisture was investigated under an environment of 105 degrees C and 50% relative humidity (RH) for 24 h. By the measurement of Fourier transform infrared absorption spectroscopy, the water-absorbed related peak (Si-OH stretching band at 3600 cm(-1)) was found in the as-deposited LPD-SiOF films after severe water-vapor test. To drive out the moisture absorbed in process of preparing the LPD-SiOF films and enhance their barrier properties against moisture, the samples were annealed for 2 h under varied ambiences, including N-2, O-2, H-2, and N2O. However, the peak intensity all disappears after annealing under various ambiences. By the measurements of spectroscopy ellipsometry, the LPD-SiOF film annealed in N-2 ambience, exhibit the highest refractive index (1.43), as well as better stability in thickness and refractive index, after permeation test. Additionally, we also found that the post-annealing treatment affects slightly its original high optical transmittance. (C) 2012 Elsevier Ltd. All rights reserved.