Plexiglass is a common term for acrylic, or PMMA, a transparent thermoplastic. Tempered glass is mineral glass strengthened by a thermal process. The materials differ in weight, surface hardness and fabrication, so selection should follow the actual application.
Acrylic: fabrication flexibility
Acrylic sheet is supplied in cast and extruded forms. It can be cut, drilled, polished and formed using suitable processing methods. Clear, coloured and specialist grades are available for different visual and functional requirements.
Tempered glass: different processing limits
Glass provides a harder, more scratch-resistant surface than standard acrylic. Tempered glass needs its final cutting and hole details established before tempering. Impact performance depends on the material grade, dimensions, support and the test method; a single comparison does not establish suitability for every application.
For pool and aquarium viewing panels
Large or curved viewing panels need a review of water depth, dimensions, supported edges, material grade and fabrication. Acrylic offers forming and bonding options, while an engineered glass system may suit other requirements. The complete viewing system should be assessed for the project.
Read the detailed acrylic and glass comparison for pool windows and aquariums.