利用溶胶 -凝胶 (sol- gel)方法制备了 Si O2 - Ge O2 薄膜 ,并测量了薄膜样品电场极化后光学二次谐波信号的相对大小和时间弛豫特性。通过对不同衬底材料及不同温度下电场极化薄膜样品二次谐波信号的时间弛豫特性比较 ,表明薄膜与衬底之间界面电荷的稳定性受衬底材料体电导率的影响 ,从而影响了薄膜样品二次谐波信号的稳定性 The Si O2 - Ge O2 thin films were prepared by sol - gel method. The relative magnitudes and the time relaxation characteristics of the optical second harmonic signals after polarization were measured. The comparison of the time-relaxation characteristics of the second harmonic signal of the samples with different substrate materials and electric field polarization at different temperatures shows that the stability of the interfacial charge between the film and the substrate is affected by the conductivity of the substrate material, Affects the stability of the second harmonic signal of the film sample