Elastic Behavior of Borate Glasses Containing Lead and Bismuth Oxides

Table 3

Nonlinear regression analysis of the variables (𝑦=𝑎𝑥²+𝑏𝑥+𝑐) for longitudinal and transverse ultrasonic velocities as well as optimum contents of modifier oxides (op = optimum points) [22, 23].

Oxides	𝑉𝑙 versus molar fraction				OP	𝑉𝑠 versus molar fraction				OP	𝑉𝑙 versus 𝑉𝑠
	𝑎	𝑏	𝑐	𝑅^2		𝑎	𝑏	𝑐	𝑅^2		𝑏	𝑐	𝑅^2
Pb	−9650	5228	3535	0.88	0.25	−5993	3384	1936	0.89	0.25	1.64	270.84	0.91
Bi	−2845	1740	3486	0.89	0.35	−2839	1982	1922	0.83	0.35	1.00	1.51	0.87
K	−9796	7200	3623	0.97	0.30	−5186	3817	1994	0.95	0.30	1.86	−78.51	0.99
Ag	−7024	5047	3406	0.93	0.25	−5743	2877	1882	0.96	0.25	2.40	−1.14	0.97
Li	−26720	17800	3781	0.92	0.25	−19218	12074	2135	0.91	0.25	1.53	566.66	0.98