Good day

The glass has this spectral characteristics due to bismuth oxide.

It is bismuth oxide that has two absorption peaks at 380 and 470 nm wavelengths.

https://cyberleninka.ru/article/n/issledovanie-vliyaniya-oksida-fosfora-na-fiziko-himicheskie-svoystva-stekol-v-sisteme-v1203-byu2-r205

(in Russian language only)

In addition, titanium oxide can increase the absorbing effect of colorants under certain conditions.

Best Regards,

Dmitry Petrov

Thanks Dmitry Petrov,

Nice to see the answer,

Can you please elaborate more because

https://cyberleninka.ru/article/n/issledovanie-vliyaniya-oksida-fosfora-na-fiziko-himicheskie-svoystva-stekol-v-sisteme-v1203-byu2-r205

is Russian, can it will be in English,

with regards

sincerely

Jalindar

Good day

Unfortunately, this article is published only in Russian.

But I can tell its main points

At this article the glass formation region of the Bi2O3-SiO2-P2O5 system and spectral characteristics were investigated.

It was found that the increasing the SiO2 content instead of P2O5 leads to the increasing the absorption ability of bismuth oxide in the glass.

Best Regards,

Dmitry Petrov