Refractive index database

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Optical constants of PLASTICS
PS - Polystyren

Wavelength: µm

Complex refractive index (n+ik)[ i ]

n   k   LogX   LogY   eV

Derived optical constants

Dispersion formula [ i ]


Conditions & Spec sheet

n_is_absolute: false
wavelength_is_vacuum: false
temperature: 20 °C


20 °C


N. Sultanova, S. Kasarova and I. Nikolov. Dispersion properties of optical polymers, Acta Physica Polonica A 116, 585-587 (2009)
(fit of the experimental data with the Sellmeier dispersion formula: Mikhail Polyanskiy)


[Expressions for n]   [CSV - comma separated]   [TXT - tab separated]   [Full database record]


Polystyrene (PS), (C8H8)n

Polystyrene (PS, (C8H8)n) is a versatile and widely-used thermoplastic polymer. Characterized by its clear, hard, and brittle nature, it can also be produced as a foam material known as expanded polystyrene (EPS) or extruded polystyrene (XPS), which is valued for its insulating and cushioning properties. PS has a relatively simple structure, which lends to its clarity when molded into products. It is also easily processed and can be molded into a wide variety of shapes and products. Due to its amorphous structure, PS has a consistent refractive index, which makes it favorable for many optical applications. Common uses of polystyrene include disposable cutlery, CD cases, and plastic model assembly kits. In optics, its properties can vary slightly depending on manufacturing processes and additives. While it is inexpensive and easily fabricated, polystyrene is not very resistant to chemicals and can be affected by sunlight over time, causing yellowing or degradation.

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Plastics offer a lightweight, cost-effective alternative to traditional optical materials like glass and crystal, making them an increasingly popular choice for a variety of optical applications. Common optical plastics include polymethyl methacrylate (PMMA), polycarbonate, and cyclic olefin copolymer (COC), each with its own set of advantages and limitations. For instance, PMMA is known for its excellent light transmittance and ease of fabrication, while polycarbonate provides higher impact resistance. Plastics are widely used in consumer electronics, automotive lighting, and even in some medical devices, where their lightweight nature and moldability offer distinct advantages. They are particularly well-suited for mass production techniques like injection molding, which allows for the creation of complex optical elements at scale. However, plastics generally have lower refractive indices and can exhibit higher levels of optical dispersion compared to glass, which can be a limitation in high-precision applications. They are also more susceptible to environmental factors such as temperature fluctuations and UV degradation, requiring special additives or coatings for long-term stability. Advances in polymer science are leading to new types of optical plastics with improved characteristics, including higher refractive indices and lower levels of dispersion, expanding their range of potential applications. Overall, plastics provide a versatile and economically viable option for many optical systems, and ongoing research promises to further extend their capabilities.

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