Basic Technical Factors for Early Screening

Define the Required Response Before Selecting a Material

Photochromic performance cannot be described by activation color alone. Early screening should establish how the finished product must respond, appear, and perform under its actual lighting and use conditions.

Finished Product

Activating Light: What UV wavelength and intensity will reach the photochromic material? Sunlight, artificial UV sources, windows, coatings, and protective layers can produce very different activation results.

Light Response

Color Response: What should the material look like before activation, and what color strength must develop under UV exposure? The substrate, background color, loading, and thickness all influence the visible result.

Material System

Activation and Fade Behavior: How quickly must the color appear, and how quickly should it fade after the activating light is removed? Photochromic change is gradual, and the timing depends on both the chemistry and the complete material system.

Process

Temperature Effects: At what temperature will the product be evaluated and used? Temperature can affect activated color strength, activation speed, and fade rate.

Visual

Transparency and Haze: Must the finished product remain transparent, or is some haze acceptable? Dissolved dyes may support greater clarity, while encapsulated pigments and slurries can scatter light and increase haze.

Durability

UV Exposure and Service Life: How often and for how long will the product be exposed to UV light? Photochromic materials can gradually lose response through repeated or prolonged exposure, so durability must be tested against the intended service conditions.

Defining these factors gives us a practical basis for selecting a material format and planning a meaningful application evaluation.

What Affects Photochromic Performance 

Performance Is Determined by the Complete System

A photochromic material may respond well in one formulation and poorly in another. Its performance depends on how much activating light reaches it, how it interacts with surrounding materials, how it is processed, and the conditions it faces in the finished product.

UV Source

Light Source and UV Dose: The wavelength, intensity, distance, and exposure time of the light source affect how strongly and quickly the material activates. Indoor UV lamps and natural sunlight may produce noticeably different results.

Overlayers

Coatings and Covering Materials: Glass, plastics, clear coats, laminates, UV absorbers, and protective layers may reduce or block the UV light needed for activation. The photochromic layer must be evaluated beneath the complete construction.

Matrix

Matrix Chemistry: Resins, binders, solvents, plasticizers, additives, pH, and curing agents can affect solubility, capsule stability, color development, and fade behavior. Compatibility with one component does not confirm compatibility with the finished formulation.

Loading

Loading and Thickness: The amount of photochromic material and the thickness of the finished layer or article influence activated color strength, transparency, haze, and fade behavior. Increasing the loading may strengthen the color but can also create unwanted appearance or processing problems.

Processing

Processing Stress: Heat, shear, aggressive mixing, grinding, curing conditions, and residence time can damage the photochromic chemistry or its protective microcapsules. The acceptable process depends on the selected material format.

End Use

End-Use Exposure: Repeated UV activation, prolonged sunlight, heat, moisture, chemicals, washing, and weathering can reduce performance over time. Service life must be established by testing the finished product under representative conditions.

We consider these interacting factors when helping customers select a practical starting material and define what must be tested before production use.

Photochromic Dyes

For Transparent and Low-Haze Material Systems

Photochromic dyes are molecular materials designed to dissolve within a compatible resin, solvent, or formulation.  When they remain fully dissolved and able to change molecular structure, they can provide reversible UV activated color with less light scattering than encapsulated pigments.

When Photochromic Dyes May Be a Practical Starting Point

• Transparent or translucent plastics
• Solvent-borne coatings and inks
• Casting and specialty resin systems
• Applications where minimizing haze is important
• Custom formulations that allow the dye to remain dissolved and molecularly mobile

What Must Be Evaluated

Solubility and Compatibility The dye must dissolve completely in the selected solvent or resin and remain dissolved throughout processing, curing, and service.  Initial dissolution does not guarantee long-term compatibility.

Molecular Freedom  The surrounding matrix must allow the dye to change between its inactive and activated structures.  A rigid or highly crosslinked system may restrict this movement and weaken or prevent the color response.

Processing Conditions  Heat, curing chemistry, residence time, and reactive formulation components may damage the dyes or alter its performance.

Crystallization and Migration  An incompatible system may cause the dye to crystallize, separate, migrate, or produce uneven color after incorporation.

UV Durability  Repeated activation and prolonged UV exposure can gradually reduce color strength and response.  The finished article must be tested under representative exposure conditions.

Technical Documents: Photochromic Dyes TDS

Encapsulated Photochromic Pigments

For Dispersed Color Change in Custom Formulations

Encapsulated photochromic pigments consist of photochromic colorants protected within microscopic capsules.  Unlike photochromic dyes, these pigments are dispersed rather than dissolved.  Encapsulation can make them easier to incorporate into certain inks, coatings, and polymer systems, but the capsules must remain chemically and physically intact.

When Encapsulated Pigments May Be a Practical Starting Point

• Custom printing inks and coatings
• Screen-printing and decorative applications
• Systems where complete dye solubility is difficult
• Opaque or translucent products where some haze is acceptable
• Formulations that can use controlled, low-shear dispersion

What Must Be Evaluated

Binder and Solvent Compatibility  The capsule shell and photochromic material must tolerate the binder, solvents, additives and other formulation components.  A solvent that appears compatible initially may still weaken the capsules or reduce performance over time.

Dispersion Method  The pigment must be distributed uniformly without damaging the microcapsules.  Gentle mixing is generally preferred; aggressive grinding, milling, or high shear dispersion can rupture the capsules and destroy or weaken the photochromic response.

Transparency and Haze  Because the microcapsules remain as dispersed particles, they can scatter light and create haze.  Encapsulated pigments are generally less suitable than dissolved dyes when high optical clarity is required.

Particle Size and Surface Quality  Capsule size may affect printability, coating smoothness, film thickness, and the appearance of the finished surface.  The application method must accommodate the dispersed particles.

Processing Conditions  Heat, pressure, shear, curing conditions, and drying temperature may damage the capsules or photochromic chemistry.  Suitability must be evaluated using the actual production process.

UV Durability  Encapsulation can help protect the photochromic material from parts of the surrounding formulation, but it does not eliminate degradation from repeated or prolonged UV exposure.

Technical Documents: Photochromic Pigments TDS

Photochromic Aqueous Slurry

For Water-Based Ink and Coating Development

Photochromic aqueous slurries contain encapsulated photochromic pigments predisposed in a water based carrier.  They provide a practical starting format for aqueous formulations by reducing the need to disperse dry microcapsules directly.

A photochromic slurry is not a finished ink or coating.  It must still be incorporated into a compatible binder system and evaluated for application, drying, adhesion, appearance, and durability.

When an Aqueous Slurry May Be a Practical Starting Point

• Water-based printing inks and coatings
• Paper, board, textile, and selected porous substrates
• Formulations that benefit from predispersed microcapsules
• Applications where some haze is acceptable
• Processes that allow controlled, low-shear mixing

What Must Be Evaluated

Binder Compatibility. The binder must form the required film without attacking the capsule shell or preventing the activated color from developing.

pH and Co-solvents  The formulation’s pH, alcohols, glycols, coalescence, surfactants, and other additives may affect capsule stability and photochromic performance.

Mixing and Filtration  Settling may occur during storage, but the slurry should be remixed without unnecessary high shear.  Milling filtration methods that damage or remove the microcapsules must be avoided.

Application and Drying  The coating or printing method, deposit thickness, drying temperature, substrate, and production speed all affect the final result.

Storage and Handling  The slurry must be protected from freezing, excessive heat, contamination, and storage conditions that could damage the dispersion.

Finished-Film Performance  Adhesion, water resistance, abrasion resistance, flexibility, haze, and UV durability come from the complete formulation−not the slurry alone.

Technical Documents: Photochromic Aqueous Slurry TDS

Ready-to-Use Photochromic Inks

A More Direct Route for Established Printing Applications

Ready-to-use photochromic inks combine the photochromic material with an established ink system. They can provide a more direct evaluation route when the available ink chemistry, substrate, printing method, curing conditions, and end-use requirements align with the application.

Ready-to-use does not mean universally compatible. The complete printing and curing process must still be evaluated.

Photochromic Plastisol Textile Inks

The current PFT100 family consists of ready-to-print PVC plastisol inks designed for textile screen printing. These inks change from a substantially colorless or lightly colored inactive state to a visible color when exposed to activating UV light.

The current family includes multiple activated colors, but color availability should be confirmed before evaluation.

What Must Be Evaluated

Fabric and Background Color  Fabric composition and color affect contrast, appearance, adhesion, curing, and possible dye migration.

Screen and Ink Deposit  Mesh selection and deposit thickness affect color strength, inactive appearance, print detail, and cure requirements.

Complete Cure  The entire ink deposit must reach the required cure temperature. Undercuring can reduce washability, while overheating can damage the photochromic response.

Activated Color  The printed article must be evaluated under the intended UV source and temperature. Color charts and digital images cannot reproduce every application result.

Washing and End Use  Wash method, bleach exposure, abrasion, stretching, and repeated UV activation can affect service life.

Other Ink Systems  Water-based, solvent-based, UV-curable, flexographic, and other photochromic ink systems may require confirmation of current availability and application fit.

Technical Documents:
Photochromic Textile Screen Ink Plastisol TDS
Photochromic Textile Screen Ink Plastisol Based Web Version TDS 
Photochromic Water Based Screen Ink TDS
Photochromic UV Screen Ink TDS
Photochromic Solvent Screen Ink TDS

Photochromic Masterbatch

A Controlled Starting Point for Selected Thermoplastics

Photochromic masterbatch combines photochromic material with a polymer carrier for introduction during thermoplastic processing.  It can simplify material handling and distribution compared with adding raw photochromic material directly to the resin.

The current general purpose masterbatch is positioned primary as an evaluation route for polypropylene.  It should no be presented as compatible with all plastics.

When Photochromic Masterbatch May Be a Practical Starting Point

• The resin and carrier system are compatible
• Processing temperatures are within the material’s practical limits
• Residence time and heat history can be controlled
• The part is thick enough to develop the desired color
• Some inactive tint or haze is acceptable
• A loading ladder can be molded and compared

What Must Be Evaluated

Resin and Grade  The exact polymer, grade, additives, fillers, colorants, and recycled content can affect compatibility and color response.

Processing Temperature  Actual melt temperature−not only the machine setting−must remain within the practical processing range of the photochromic system.

Residence Time and Heat History  Long residence times, repeated processing, regrind, and multiple heat histories can weaken or permanently alter the material.

Loading and Part Thickness The required loading depends on the part thickness and desired activated color.  A thin part may require more material but develop greater haze or inactive background color.

Dispersion and Appearance  Uniform distribution is needed to avoid striking, uneven activation, or visible concentration differences.

Finished-Part Testing  The molded article must be evaluated for activation, fading, color uniformity, haze, durability, and performance under its intended use conditions.

QCR Solutions reviews the exact resin, molding process, temperature profile, residence time, part thickness, and desired appearance before identifying Photochromic Masterbatch as a practical evaluation path.