Sample

starting mixted oxide (mol%)

T_g (˚C)

(±2)

Fe₂O₃

PbO

P₂O₅

S₀

0

45

55

376

S₅

5

40

55

415

S₁₀

10

35

55

432

S₁₅

15

30

55

470

S₂₀

20

25

55

501