Is Plexiglass UV Resistant?

As an Amazon Associate we earn from qualifying purchases made on our website.

Plexiglass, also known as acrylic, has a wide range of uses in various industries. For example, it’s often used in construction as a lightweight alternative to glass for windows, skylights, and doors. Plexiglass is also used for signage, particularly outdoor signs, due to its weather-resistant properties. But is plexiglass UV resistant?

Plexiglass can be UV resistant if it’s formulated with specific additives, such as UV stabilizers or absorbers, which block or absorb harmful UV rays. The level of UV resistance in plexiglass depends on the grade and formulation of the material, and it can be determined by various testing methods. 

It’s essential to choose the right grade of plexiglass based on the intended application and the expected level of UV exposure to ensure its long-term durability and performance. So, let’s take a closer look at the UV resistance of plexiglass and what else you should know if you’re planning to use this versatile material.

What Does ‘UV Resistance’ Mean?

Plexiglass street basketball board with hoop without net

Sunlight contains UV rays, a type of electromagnetic radiation that can break down chemical bonds in materials and cause them to become discolored, brittle, or even crack. 

UV resistance is essential for materials exposed to sunlight, as UV radiation can cause significant damage and degradation to the materials over time.¬†Therefore, it’s crucial to ensure that materials used in outdoor applications, such as windows, signage, or protective barriers, are UV resistant.

Plexiglass is naturally transparent. This allows UV radiation to pass through it, which can lead to degradation of the material over time. However, specific grades of plexiglass are formulated to resist UV radiation. 

Special Grades of Plexiglass

Certain plexiglass grades contain additives, such as UV stabilizers or absorbers. UV stabilizers are chemical compounds that work by stabilizing the material’s molecular structure, making it more resistant to UV degradation. 

These compounds act as a barrier, reflecting the UV rays away from the material’s surface and preventing them from penetrating the plexiglass and causing damage. 

On the other hand, UV absorbers work by absorbing the UV rays and converting them into heat that dissipates away from the material. This process reduces the amount of UV radiation that penetrates the material and causes damage. 

Long- and Short-Term Formulations

Some plexiglass grades are formulated to withstand UV radiation for extended periods without significant degradation. In contrast, others may only be suitable for indoor or short-term outdoor exposure. 

Therefore, it’s essential to choose the right grade of plexiglass based on the intended application and the expected level of UV exposure.

To determine the level of UV resistance in plexiglass, manufacturers use various testing methods, including accelerated weathering tests. 

These tests simulate the effects of long-term UV exposure on materials, allowing manufacturers to evaluate the material’s performance and determine its expected lifespan under specific conditions.

Can Plexiglass Be Tinted?

Tinting plexiglass is a common technique used to change the material’s color or reduce the light that passes through it. Tinting can be done for various reasons, including aesthetics, privacy, and glare reduction. 

For example, in architectural applications, tinted plexiglass may reduce glare or add a decorative element to a building’s exterior. In automotive applications, tinted plexiglass may be used to reduce the amount of heat and glare that enters the vehicle’s interior.

However, not all types of plexiglass can be tinted, and the method used to tint the material may vary depending on the specific grade of plexiglass.

Plexiglass can be tinted using various methods, including adding dyes or pigments to the material during manufacturing or applying a tinted film to the surface of the plexiglass. 


Adding dyes or pigments to plexiglass during manufacturing is the most common method of tinting the material. 

This method involves mixing the colorant with the acrylic resin before it’s extruded into sheets, resulting in a homogeneous tint throughout the material.

Tinted Film

Another way to tint plexiglass is to apply a tinted film (on Amazon) to the material’s surface. This method involves adhering a thin film to the plexiglass, which can be removed or replaced. 

Tinted films come in various colors and shades and can be customized to meet specific needs.

Limitations to Tinting

The type of plexiglass used can also affect the tinting process. For example, some types of plexiglass aren’t suitable for tinting, such as clear or transparent grades, as the colorant may not adhere properly or may result in an uneven tint. 

However, opaque or translucent grades of plexiglass are better suited for tinting, as the colorant can be evenly dispersed throughout the material.

Will Plexiglass Soften if Left in the Sun?

The bus platform is protected on one side by transparent plexiglass attached to a gray metal tube railing

Plexiglass is a thermoplastic that can soften and melt when exposed to high temperatures. 

This property is due to the material’s molecular structure, consisting of long chains of repeating units held together by weak intermolecular forces. The forces weaken when heated, allowing the chains to move more freely, making the material softer and more pliable.

Heating by UV Radiation

One of the main factors that affect the softening of plexiglass is exposure to UV radiation from the sun. 

UV radiation causes the material’s molecular bonds to break down, reducing the material’s strength and stiffness. As the material weakens, it becomes more susceptible to deformation and can eventually soften or even melt.

The degree to which plexiglass softens in the sun depends on several factors, including the type of plexiglass. It also depends on the material’s thickness and UV exposure duration and intensity. 

Some types of plexiglass are more resistant to UV radiation than others, and thicker sheets of plexiglass are less likely to soften than thinner sheets.

To mitigate the effects of UV radiation on plexiglass, manufacturers often add UV stabilizers to the material during manufacturing. 

UV stabilizers absorb UV radiation and help prevent the material from breaking down and softening. However, even with UV stabilizers, prolonged exposure to the sun can still cause plexiglass to soften over time.

In addition to UV radiation, other factors can also affect the softening of plexiglass. For example, exposure to high temperatures, such as those in a car parked in direct sunlight, can accelerate softening. 

Similarly, exposure to solvents or chemicals can cause the material to soften and become more susceptible to deformation.

Plexiglass vs. Lexan: Which Is More UV Resistant?

When it comes to UV resistance, plexiglass is generally considered to be a moderately UV-resistant material. 

It can withstand prolonged exposure to sunlight without yellowing or becoming brittle. Still, it may soften or lose some of its strength over time.

On the other hand, Lexan is a brand name for a type of polycarbonate plastic known for its high-impact resistance and transparency. Lexan is used in applications where strength and toughness are critical, such as bullet-resistant glass, safety shields, and motorcycle helmets. 

When it comes to UV resistance, Lexan is generally considered to be a highly UV-resistant material. As a result, it can withstand prolonged exposure to sunlight without yellowing, becoming brittle, or losing its strength.

The main reason for the difference in UV resistance between plexiglass and Lexan is their chemical composition. 

It’s All Down to Chemistry

Plexiglass is made from polymethyl methacrylate, which is inherently less resistant to UV radiation than polycarbonate, the polymer from which Lexan is made. 

Polycarbonate has a chemical structure that includes alternating carbon and oxygen atoms, which gives it the ability to absorb and dissipate UV radiation better than plexiglass does.

In addition to the chemical compositions of these materials, the manufacturing process and the additives used in each can also affect its UV resistance. 

Consider the Amount of UV Resistance You Need

When choosing between the plexiglass and Lexan for a specific application, it’s important to consider the level of UV exposure to which the material will be exposed. 

If the material will be exposed to prolonged periods of direct sunlight, or if UV resistance is a critical factor, then Lexan may be a better choice. 

On the other hand, if transparency, weather resistance, and impact resistance are the primary concerns, then plexiglass may be the better option.

Leave a Comment