Smart Glass Technologies Review
- SFI Team
- Jul 1
- 6 min read
Smart glass—also known as switchable or dynamic glazing—refers to glass that alters its transparency or tint in response to electrical, thermal, or lighting stimuli. Initially conceived in the 1980s to improve the energy efficiency of building envelopes, smart glass eliminates the need for blinds or shades while offering light regulation, privacy, and UV protection. Smart Films International specializes in PDLC smart film and adhesive formats that retrofit or integrate into existing glazing.
Polymer-dispersed liquid crystal (PDLC) technology dominates the modern privacy glass market (> 95% share) due to its fast switching, zero-maintenance appeal, and versatility. A range of other technologies—such as electrochromic, photochromic, thermochromic, PNLC, and full-blackout ECF—deliver shading, insulation, or passive control. This article covers the full history, technology overview including maintenance, deep dive into PDLC formats, comparison, economics, future trends, and concluding insights.
Historical Evolution of Smart Glass
Early vision of dynamic glazing and initial developments began in the 1980s with researchers envisioning a future where windows could modulate light and heat dynamically. Swedish physicist Claes-Göran Granqvist was among the pioneers coining the term "smart window."
Major milestones include the early development of thermochromic and photochromic materials and the first commercial uses of PDLC in the 1990s. With increasing interest in energy-efficient buildings, the 2000s and 2010s saw the rise of active smart glass technologies including electrochromic systems and mass-scale deployment of PDLC in interior partitions and privacy applications.
Discoveries in liquid crystal chemistry and nano-materials enabled refinements in optical clarity, switching speed, and durability. The availability of self-adhesive PDLC films has made smart glass more accessible to retrofits, expanding its practical use cases dramatically.
Overview of Smart Glass Technologies
Smart glass PDLC
Smart glass PDLC (Polymer Dispersed Liquid Crystal) technology relies on a dispersion of liquid crystal droplets within a polymer matrix. When no voltage is applied, the droplets scatter light and make the glass appear frosted. When voltage is applied, the liquid crystals align, and the glass becomes clear. PDLC is ideal for on-demand privacy with fast response times and minimal energy consumption during the opaque state. It does not offer gradual dimming but provides a binary clear/opaque function, making it excellent for interior privacy. Maintenance is low; with proper electrical installation and protection from moisture, PDLC films can last over a decade.
PNLC
PNLC Reverse Smart film (Polymer Network Liquid Crystal) is similar to PDLC but uses a polymer network to anchor the liquid crystals, offering better optical clarity and sometimes improved contrast. PNLCs are typically more expensive and used in specialized applications. Maintenance is similar to PDLC, although manufacturing requires more precision, especially during lamination.
Electrochromic glass
Electrochromic glass changes its light transmission properties when a voltage is applied, allowing gradual tinting. Layers of electrochromic materials (e.g., tungsten oxide) interact to darken or lighten based on applied voltage. This makes electrochromic glass ideal for sun control and glare reduction in façades and skylights. However, it is slower to respond than PDLC (seconds to minutes), and while it retains its state without continuous power, production and operation costs remain high.
Manufacturers like SageGlass and View have developed notable installations worldwide, but all have reported ongoing financial losses. Despite thousands of projects, electrochromic remains economically uncertain due to high material and integration costs.
Photochromic film
React to UV light, darkening when exposed to sunlight. These are passive, require no electrical control, and are often used in automotive applications such as sunroofs or windscreens. Unlike smart glass for buildings, photochromic films lack user control and their reaction time and darkness depend on UV intensity. In 2025, they are not considered dominant in the anti-sun glazing market and are limited in architectural applications due to their unpredictability and lack of switchability.
Thermochromic glass
It darkens in response to heat. This passive technology automatically adjusts its tint based on temperature, requiring no electrical control. While promising for energy efficiency, thermochromic glass has seen limited commercial viability. As of 2025, there is no active production of thermochromic smart glass.
Manufacturers have phased out development due to challenges in consistency, performance at different climates, and limited customer control.
ECF Blackout
ECF Blackout technology provides a complete blackout function when activated, often using advanced polymer or LCD-based layers. This technology is useful in high-privacy or projection environments such as darkrooms or cinema rooms. It generally requires more robust power management and specialized installation but serves a distinct niche.
PDLC Smart Glass: The Market Leader
PDLC Mechanism: PDLC works by suspending liquid crystals in a polymer film layered between transparent conductive materials. When power is applied, the crystals align, allowing light to pass through. Without power, they scatter light, rendering the panel opaque. This rapid switching makes PDLC ideal for instant privacy.
PDLC Formats
Smart Glass Triplex - Integrated between two layers of glass with EVA or PVB interlayer for structural integrity.
Self-Adhesive Smart Film - A retrofit option applied directly to existing glass with peel-and-stick functionality.
Laminated Smart Film - Integrated during the manufacturing of safety glass at the factory.
Smart Glass IGU - Incorporated into insulated glass units for thermal and acoustic insulation in addition to switchable privacy.
Benefits: PDLC offers millisecond switching, no moving parts, and can be retrofitted or specified in new construction. It blocks UV radiation, reduces glare, and contributes to modern design aesthetics. Its ease of use, longevity, and cost-efficiency make it a preferred choice.
Comparison Between Technologies
Response time: PDLC and PNLC provide the fastest response (milliseconds). Electrochromic takes seconds to minutes. Photochromic and thermochromic are passive and slow. PNLC is still very expensive as it isnt produce in mass production.
Power and clarity: PDLC uses power only when transparent; electrochromic needs pulses but holds state; passive types need no power but lack control. PNLC may offer better clarity but at higher cost.
Best applications: PDLC excels in interior spaces for instant privacy. Electrochromic suits external windows for solar control. Photochromic is limited to cars. Thermochromic is largely phased out. ECF serves specialized blackout needs.
Market Penetration and Adoption
PDLC dominates due to its adaptability, affordability, and ease of use. Holding more than 95% of the smart privacy glass market, it’s used in corporate offices, hospitals, luxury homes, and retail.
Industries use PDLC in meeting rooms, restrooms, partitions, and facades. Adhesive films have expanded its reach into retrofit projects, while triplex and IGU formats are specified in new developments.
Products must comply with safety, electrical, and durability standards. Manufacturers offer custom sizes and shapes for seamless integration.
Future and Trends
Smart glass is increasingly integrated with home automation and IoT systems. PDLC and electrochromic technologies are now compatible with mobile apps, sensors, and AI-based climate systems.
Material innovation continues with improved clarity, reduced power consumption, and enhanced environmental resistance. PNLC and hybrid LC technologies are being explored for dual-functionality.
As green building standards tighten, smart glass is expected to play a key role in sustainable architecture, reducing reliance on blinds and HVAC systems.
Is It Economic? Understanding Cost
Initial installation of smart glass ranges widely: PDLC ~$70–$120/sq.ft.; electrochromic ~$130–$180/sq.ft.; self-adhesive films being the most cost-effective. Passive technologies cost less but offer fewer benefits.
Installation complexity varies. Adhesive PDLC film is easiest. Triplex and IGU require professional glazing. Electrochromic demands factory-sealed units and wiring.
ROI is achieved via energy savings, elimination of curtains/blinds, increased space usability, and improved aesthetics. In offices and healthcare, ROI typically occurs in 3–5 years. PDLC provides the most predictable and affordable path to return.
Summary
Smart glass technologies have evolved from experimental coatings to practical, scalable systems. PDLC dominates the privacy-focused market due to its simplicity, speed, and cost efficiency. While electrochromic and passive technologies serve niche roles, their economic viability is still in question. As integration with automation and sustainability goals increase, smart glass is poised to become a fundamental component of modern architecture.
FAQ
What is PDLC smart glass?
PDLC is a switchable film that turns opaque without power and becomes transparent when voltage aligns the liquid crystals inside it.
Why does PDLC lead the market?
PDLC offers fast switching, long lifespan and flexible installation formats, making it the go-to solution for interior privacy control.
How does PDLC compare to electrochromic?
PDLC is faster and cheaper, but lacks dimming levels. It more used internally. Electrochromic tints gradually but is much costly, slow and used on facade. These technologies are not compete or replaced each other.
Is electrochromic glass cost-effective?
Despite large installations, major producers report losses, and high costs limit ROI.
Are thermochromic and photochromic technologies still used?
Thermochromic is no longer in production as of 2025. Photochromic films are mainly used in automotive glass for automotives but it is not a big market.
Can smart glass be automated?
Yes. PDLC and electrochromic systems can integrate with smart home platforms, sensors, and voice assistants.