One or more coated layers having a variation in index of refraction can provide improvements in antireflection property. For example, different sol gel formulations can be employed in a multiple coating step approach to achieve a desired gradation of index of refraction using individual or combinations of particles containing sol formulations. Different organic porosity forming agents, surfactants and binders can be used to provide further control in forming the gradual index of refraction. In addition, different heat and chemical treatment conditions could also provide control over the gradation of index of refraction.