In the ever-evolving world of technology, the sphere of Facility Management Software (FMS) is no exception. The rapid development of digital technology, combined with an increased demand for optimized operational efficiency and sustainability, paints a picture of a future where FMS is more integrated, intelligent, and indispensable than ever before. Let us delve deeper into this exciting vision to discern the potential trajectories and emerging trends in the realm of FMS.

The chronicle of FMS is a testament to its continuous evolution. In the early days, the software primarily focused on simple tasks such as maintenance scheduling and work order management. However, as requirements became more intricate and demanding, the role of FMS expanded to offer a holistic solution that encompasses not only maintenance management but also space management, capital project management, environmental sustainability, and real-time monitoring. The integrative nature of FMS makes it a potent tool for decision-makers aiming to optimize resource allocation, enhance productivity, and reduce operational costs.

The Internet of Things (IoT) has particularly fueled the revolution of FMS. The IoT has endowed FMS with the power of interconnectivity and real-time data collection and analysis. This synergy between IoT and FMS has given birth to the concept of 'smart buildings' - structures that optimize energy use, streamline operations, and enhance the overall user experience. McKinsey Global Institute estimates the IoT could generate up to $11.1 trillion a year in economic value by 2025, a portion of which will undoubtedly be attributed to FMS.

Artificial Intelligence (AI) and Machine Learning (ML) are other technological revolutionaries that are reshaping the landscape of FMS. Intelligent algorithms not only aid in data analysis but also facilitate predictive maintenance, thereby reducing the likelihood of equipment failure and consequential downtime. Furthermore, AI-enabled chatbots can automate the customer service process, leading to improved efficiency and customer satisfaction.

In terms of emerging trends, the increasing emphasis on sustainability and green technology is steering the future of FMS towards eco-friendly solutions. The global focus on reducing carbon footprints and conserving resources is encouraging the development of FMS that can monitor and manage energy consumption, reduce waste, and promote recycling.

Another noteworthy trend is the rising prominence of mobile technology in FMS. The ubiquity of smartphones and tablets, coupled with the advent of cloud computing, allows facility managers to access and manage their systems on-the-go. This remote accessibility ensures continuous monitoring and instant responsiveness, further enhancing operational efficiency.

While these advancements paint an optimistic picture of the future of FMS, they also bring forth novel challenges. For instance, the integration of IoT poses a significant risk concerning data security and privacy. As FMS continues to collect and analyze a plethora of data, ensuring its security and privacy becomes increasingly complicated yet crucial. Similarly, the augmentation of AI and ML demands an ethical, legal, and societal discourse on their use and potential misuse.

In conclusion, the future of Facility Management Software is promising and complex, characterized by increased integration, intelligence, and sustainability. Its trajectory is driven by technological advancements like IoT, AI, and ML, and steered by global trends such as sustainability and mobile technology. However, these developments also necessitate a broader discussion on data security, privacy, and the ethical implications of AI. As we stand on the precipice of this digital revolution, it is incumbent upon us to harness these technologies responsibly, ensuring that the future of FMS aligns with our larger societal, economic, and environmental goals.