Effect of Poling Temperature on Optical Second‐Harmonic Intensity of Lithium Sodium Tellurite Glass

Second‐harmonic generation has been observed in poled 10Li 2 O10Na 2 O80TeO 2 glass. The effect of poling temperature on the second‐harmonic intensity has been examined. The second‐harmonic intensity increases, attains a maximum, and then decreases as the poling temperature increases. In other words, an optimum poling temperature that results in a maximum second‐harmonic intensity exists. The optimum poling temperature linearly increases as the glass‐transition temperature increases for several types of tellurite glasses, including the present 10Li 2 O10Na 2 O80TeO 2 glass. This fact suggests that the process to create a polarization that results in the second‐harmonic generation is affected by the structural relaxation at the glass‐transition range. The thermal stability of 10Li 2 O10Na 2 O80TeO 2 glass is higher than that of 18Na 2 O82TeO 2 (30NaO 1/2 70TeO 2 ) glass, as revealed via differential scanning calorimetry. As a result, the temperature range within which the poling is effective is wider for the former glass.