TY - JOUR T1 - Investigation of structural and optical properties of glasses with composition of ( P2O5 – V2O5 – Li2O – K2O ) TT - بررسی ویژگی های ساختاری و اپتیکی شیشه هایی با ترکیب (P2O5 –V2O5 – Li2O - K2O) JF - opsi JO - opsi VL - 21 IS - 0 UR - http://opsi.ir/article-1-517-en.html Y1 - 2015 SP - 325 EP - 328 KW - Glassy films KW - Mixed alkali effect N2 - Glassy thin films with composition of 40P2O5 – 30V2O5 – (30 – x)Li2O – xK2O , were prepared by conventional melt quenching method . X-ray diffraction patterns confirmed the glassy character of the samples.UV and IR properties of samples have been investigated. Non linearly variation of optical band gap and Urbach energy have exhibited a mixed alkali effect. IR spectroscopies confirmed the existence of P-O-P,PO -, PO2 ,V-O-V,V-O-P,V═O bond groups. M3 ER -