Although we see these glass panels in old houses and some contemporary revival, there is not much written about this architectural gem.
These classical glass panels are often found in Spanish Colonial heritage houses in windows and dividers and are often with capiz windows.
The Ylang-Ylang/Sampaguita Glass is a type of pressed glass with motifs such as flowers, leaves, and tendrils.
A pressed glass is actually molded glass. Pressed glass is made by pressing molten glass into a machine mold. In the case of the Ylang-Ylang/Sampaguita Glass, the mold is in the form of either a Ylang-ylang flower or a Sampaguita flower which are common flora in the Philippines.
The glass patterns illustrated the subtle architectural resistance of the time: While the source material was clearly based off colonial influence, the subject matter was clearly Filipino–notice the flowers, sampaguita and ylang-ylang, and see how much the designers of the time took control of their design language.
Reference:
https://www.facebook.com/pg/IxxamNeoRetro/photos/?tab=album&album_id=662664467130332
https://www.thesprucecrafts.com/faq-about-old-pressed-glass-149098