An extended study of lithium niobium silicate glass crystallization with the molar composition 35Li(2)O-25Nb(2)O(5)-40SiO(2) is presented. Depending on the heat treatments, both surface and/or bulk crystallizations of the LiNbO(3) crystalline phase were observed. X-ray diffraction together with second harmonic generation (SHG) measurements have revealed a net preferred orientation of the ferroelectric crystallites at the surface which is quite different in the bulk. A striking and promising SHG response estimated to be five times larger than a-quartz has been observed in the bulk.