“…Compared with other phosphate glasses, the PAN matrix presented similar values of C [6]. However, silicates, aluminosilicates (LSCAS), germanates (GaLaS), heavy metal oxide (PbO-Bi 2 O 3 -Ga 2 O 3 -BaO), and fluorates (ZBLAN) presents a very high value of C, in modulus, compared with PAN [6,20]. Finally, the ds/dT could be obtained from C so that ds/dT¼(1.670.5) Â 10 À 6 /K.…”