Li2O-Nb2O5-ZrO2-SiO2 glasses were synthesised and subsequently crystallised with different CuO contents (0-0.3 mol% in steps of 0.05) as nucleating agents and characterised using XRD, SEM and DSC. The optical and dielectric properties were investigated to explore the influence of copper valence states and their coordination with oxygen on the structural and optoelectronic properties of the samples. Results indicated that there was a possibility for the copper ions to exist in Cu+ and Cu3+ states (in addition to Cu2+ state) in these glass-ceramics and participate in glass formation. Photoinduced second harmonic generation studies were undertaken with a 10 ns Er:glass laser to examine the suitability of these materials for optically operated devices. Analysis of the results of non-linear optical studies showed that 0.2 mol% of CuO was the optimal concentration to obtain the highest values of second order susceptibility coefficients.